audit: jpdfium split

app/core/build.gradle

@@ -136,6 +136,17 @@ sourceSets {
 
 }
 
+// Forward bench-related system properties through to the test JVM so
+// `-Dsplit.bench=true` (and similar) flags reach Boolean.getBoolean().
+tasks.named('test', Test) {
+    ['split.bench', 'split.bench.pages', 'split.bench.chunk',
+     'split.bench.imgW', 'split.bench.imgH'].each { key ->
+        def v = System.getProperty(key)
+        if (v != null) systemProperty(key, v)
+    }
+    maxHeapSize = '2g'
+}
+
 
 // Disable regular jar
 jar {

app/core/src/main/java/stirling/software/SPDF/controller/api/SplitPDFController.java

@@ -3,11 +3,10 @@ package stirling.software.SPDF.controller.api;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
@@ -30,12 +29,13 @@ import stirling.software.common.annotations.AutoJobPostMapping;
 import stirling.software.common.annotations.api.GeneralApi;
 import stirling.software.common.enumeration.ResourceWeight;
 import stirling.software.common.service.CustomPDFDocumentFactory;
-import stirling.software.common.util.ExceptionUtils;
 import stirling.software.common.util.FormUtils;
 import stirling.software.common.util.GeneralUtils;
 import stirling.software.common.util.TempFile;
 import stirling.software.common.util.TempFileManager;
 import stirling.software.common.util.WebResponseUtils;
+import stirling.software.jpdfium.PdfDocument;
+import stirling.software.jpdfium.PdfSplit;
 
 @GeneralApi
 @Slf4j
@@ -90,13 +90,8 @@ public class SplitPDFController {
                 String baseFilename = GeneralUtils.removeExtension(file.getOriginalFilename());
                 try (ZipOutputStream zipOut =
                         new ZipOutputStream(Files.newOutputStream(outputTempFile.getPath()))) {
-                    if (hasForm) {
-                        writeSplitsViaReload(
-                                sourceTempFile.getFile(), pageNumbers, baseFilename, zipOut);
-                    } else {
-                        writeSplitsViaSharedSource(
-                                sourceTempFile.getFile(), pageNumbers, baseFilename, zipOut);
-                    }
+                    writeSplits(
+                            sourceTempFile.getFile(), pageNumbers, baseFilename, zipOut, hasForm);
                 }
             }
 
@@ -109,59 +104,71 @@ public class SplitPDFController {
         }
     }
 
-    private void writeSplitsViaReload(
-            File source, List<Integer> pageNumbers, String baseFilename, ZipOutputStream zipOut)
+    private void writeSplits(
+            File source,
+            List<Integer> pageNumbers,
+            String baseFilename,
+            ZipOutputStream zipOut,
+            boolean hasForm)
             throws IOException {
-        int previousPageNumber = 0;
-        for (int splitIndex = 0; splitIndex < pageNumbers.size(); splitIndex++) {
-            int splitPoint = pageNumbers.get(splitIndex);
-            Set<Integer> keep = new HashSet<>();
-            for (int i = previousPageNumber; i <= splitPoint; i++) {
-                keep.add(i);
-            }
-            previousPageNumber = splitPoint + 1;
-
-            try (PDDocument splitDoc = pdfDocumentFactory.load(source)) {
-                for (int p = splitDoc.getNumberOfPages() - 1; p >= 0; p--) {
-                    if (!keep.contains(p)) {
-                        splitDoc.removePage(p);
-                    }
-                }
-                FormUtils.pruneOrphanedFormFields(splitDoc);
-                writeEntry(zipOut, baseFilename, splitIndex + 1, splitDoc);
-            } catch (Exception e) {
-                ExceptionUtils.logException("document splitting and saving", e);
-                throw e;
-            }
-        }
-    }
-
-    private void writeSplitsViaSharedSource(
-            File source, List<Integer> pageNumbers, String baseFilename, ZipOutputStream zipOut)
-            throws IOException {
-        try (PDDocument sourceDoc = pdfDocumentFactory.load(source)) {
+        try (PdfDocument sourceDoc = PdfDocument.open(source.toPath())) {
             int previousPageNumber = 0;
             for (int splitIndex = 0; splitIndex < pageNumbers.size(); splitIndex++) {
                 int splitPoint = pageNumbers.get(splitIndex);
-                try (PDDocument splitDoc =
-                        pdfDocumentFactory.createNewDocumentBasedOnOldDocument(sourceDoc)) {
-                    for (int i = previousPageNumber; i <= splitPoint; i++) {
-                        splitDoc.addPage(sourceDoc.getPage(i));
-                    }
-                    previousPageNumber = splitPoint + 1;
-                    writeEntry(zipOut, baseFilename, splitIndex + 1, splitDoc);
-                } catch (Exception e) {
-                    ExceptionUtils.logException("document splitting and saving", e);
-                    throw e;
+                writeSplit(
+                        sourceDoc,
+                        previousPageNumber,
+                        splitPoint,
+                        baseFilename,
+                        splitIndex + 1,
+                        zipOut,
+                        hasForm);
+                previousPageNumber = splitPoint + 1;
+            }
+        }
+    }
+
+    private void writeSplit(
+            PdfDocument sourceDoc,
+            int fromIndex,
+            int toIndex,
+            String baseFilename,
+            int splitNumber,
+            ZipOutputStream zipOut,
+            boolean hasForm)
+            throws IOException {
+        try (TempFile splitTemp = new TempFile(tempFileManager, ".pdf")) {
+            try (PdfDocument splitDoc = PdfSplit.extractPageRange(sourceDoc, fromIndex, toIndex)) {
+                splitDoc.save(splitTemp.getPath());
+            }
+            Path finalPath = splitTemp.getPath();
+            TempFile prunedTemp = null;
+            try {
+                if (hasForm) {
+                    prunedTemp = new TempFile(tempFileManager, ".pdf");
+                    pruneForms(splitTemp.getFile(), prunedTemp.getFile());
+                    finalPath = prunedTemp.getPath();
+                }
+                writeEntry(zipOut, baseFilename, splitNumber, finalPath);
+            } finally {
+                if (prunedTemp != null) {
+                    prunedTemp.close();
                 }
             }
         }
     }
 
-    private void writeEntry(ZipOutputStream zipOut, String baseFilename, int index, PDDocument doc)
+    private void pruneForms(File splitFile, File outputFile) throws IOException {
+        try (PDDocument doc = pdfDocumentFactory.load(splitFile)) {
+            FormUtils.pruneOrphanedFormFields(doc);
+            doc.save(outputFile);
+        }
+    }
+
+    private void writeEntry(ZipOutputStream zipOut, String baseFilename, int index, Path pdfPath)
             throws IOException {
         zipOut.putNextEntry(new ZipEntry(baseFilename + "_" + index + ".pdf"));
-        doc.save(zipOut);
+        Files.copy(pdfPath, zipOut);
         zipOut.closeEntry();
     }
 }

app/core/src/main/java/stirling/software/SPDF/controller/api/SplitPdfByChaptersController.java

@@ -1,6 +1,9 @@
 package stirling.software.SPDF.controller.api;
 
+import java.io.File;
 import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
@@ -8,9 +11,6 @@ import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
 
 import org.apache.pdfbox.pdmodel.PDDocument;
-import org.apache.pdfbox.pdmodel.PDPage;
-import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDDocumentOutline;
-import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineItem;
 import org.springframework.core.io.Resource;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
@@ -39,6 +39,8 @@ import stirling.software.common.util.GeneralUtils;
 import stirling.software.common.util.TempFile;
 import stirling.software.common.util.TempFileManager;
 import stirling.software.common.util.WebResponseUtils;
+import stirling.software.jpdfium.PdfDocument;
+import stirling.software.jpdfium.PdfSplit;
 
 @GeneralApi
 @Slf4j
@@ -51,72 +53,36 @@ public class SplitPdfByChaptersController {
 
     private final TempFileManager tempFileManager;
 
-    private static List<Bookmark> extractOutlineItems(
-            PDDocument sourceDocument,
-            PDOutlineItem current,
-            List<Bookmark> bookmarks,
-            PDOutlineItem nextParent,
+    private static void collectBookmarks(
+            List<stirling.software.jpdfium.doc.Bookmark> source,
+            List<Bookmark> out,
             int level,
-            int maxLevel)
-            throws Exception {
-
-        while (current != null) {
-
-            String currentTitle = current.getTitle().replace("/", "");
-            int firstPage =
-                    sourceDocument.getPages().indexOf(current.findDestinationPage(sourceDocument));
-            PDOutlineItem child = current.getFirstChild();
-            PDOutlineItem nextSibling = current.getNextSibling();
-            int endPage;
-            if (child != null && level < maxLevel) {
-                endPage =
-                        sourceDocument
-                                .getPages()
-                                .indexOf(child.findDestinationPage(sourceDocument));
-            } else if (nextSibling != null) {
-                endPage =
-                        sourceDocument
-                                .getPages()
-                                .indexOf(nextSibling.findDestinationPage(sourceDocument));
-            } else if (nextParent != null) {
-
-                endPage =
-                        sourceDocument
-                                .getPages()
-                                .indexOf(nextParent.findDestinationPage(sourceDocument));
-            } else {
-                endPage = -2;
-                /*
-                happens when we have something like this:
-                Outline Item 2
-                    Outline Item 2.1
-                        Outline Item 2.1.1
-                    Outline Item 2.2
-                        Outline 2.2.1
-                        Outline 2.2.2 <--- this item neither has an immediate next parent nor an immediate next sibling
-                Outline Item 3
-                 */
+            int maxLevel) {
+        for (stirling.software.jpdfium.doc.Bookmark bm : source) {
+            if (!bm.isInternal()) {
+                continue;
             }
-            if (!bookmarks.isEmpty()
-                    && bookmarks.get(bookmarks.size() - 1).getEndPage() == -2
-                    && firstPage
-                            >= bookmarks
-                                    .get(bookmarks.size() - 1)
-                                    .getStartPage()) { // for handling the above-mentioned case
-                Bookmark previousBookmark = bookmarks.get(bookmarks.size() - 1);
-                previousBookmark.setEndPage(firstPage);
+            String title = bm.title() == null ? "" : bm.title().replace("/", "");
+            int firstPage = Math.max(0, bm.pageIndex());
+            out.add(new Bookmark(title, firstPage, -2));
+            if (bm.hasChildren() && level < maxLevel) {
+                collectBookmarks(bm.children(), out, level + 1, maxLevel);
             }
-            bookmarks.add(new Bookmark(currentTitle, firstPage, endPage));
-
-            // Recursively process children
-            if (child != null && level < maxLevel) {
-                extractOutlineItems(
-                        sourceDocument, child, bookmarks, nextSibling, level + 1, maxLevel);
-            }
-
-            current = nextSibling;
         }
-        return bookmarks;
+    }
+
+    private static void assignEndPages(List<Bookmark> bookmarks, int totalPages) {
+        for (int i = 0; i < bookmarks.size(); i++) {
+            Bookmark current = bookmarks.get(i);
+            int next = -1;
+            for (int j = i + 1; j < bookmarks.size(); j++) {
+                if (bookmarks.get(j).getStartPage() >= current.getStartPage()) {
+                    next = bookmarks.get(j).getStartPage();
+                    break;
+                }
+            }
+            current.setEndPage(next == -1 ? totalPages : next);
+        }
     }
 
     @AutoJobPostMapping(
@@ -134,46 +100,41 @@ public class SplitPdfByChaptersController {
         MultipartFile file = request.getFileInput();
 
         boolean includeMetadata = Boolean.TRUE.equals(request.getIncludeMetadata());
-        Integer bookmarkLevel =
-                request.getBookmarkLevel(); // levels start from 0 (top most bookmarks)
+        Integer bookmarkLevel = request.getBookmarkLevel();
         if (bookmarkLevel < 0) {
             throw ExceptionUtils.createIllegalArgumentException(
                     "error.invalidArgument", "Invalid argument: {0}", "bookmark level");
         }
 
-        try (PDDocument sourceDocument = pdfDocumentFactory.load(file)) {
-            PDDocumentOutline outline = sourceDocument.getDocumentCatalog().getDocumentOutline();
+        try (TempFile sourceTempFile = new TempFile(tempFileManager, ".pdf")) {
+            Files.copy(
+                    file.getInputStream(),
+                    sourceTempFile.getPath(),
+                    StandardCopyOption.REPLACE_EXISTING);
 
-            if (outline == null) {
-                log.warn("No outline found for {}", file.getOriginalFilename());
-                throw ExceptionUtils.createIllegalArgumentException(
-                        "error.pdfBookmarksNotFound", "No PDF bookmarks/outline found in document");
-            }
             List<Bookmark> bookmarks = new ArrayList<>();
-            try {
-                bookmarks =
-                        extractOutlineItems(
-                                sourceDocument,
-                                outline.getFirstChild(),
-                                bookmarks,
-                                outline.getFirstChild().getNextSibling(),
-                                0,
-                                bookmarkLevel);
-                // to handle last page edge case
-                bookmarks.get(bookmarks.size() - 1).setEndPage(sourceDocument.getNumberOfPages());
-
-            } catch (Exception e) {
-                ExceptionUtils.logException("outline extraction", e);
-                throw e;
+            int totalPages;
+            try (PdfDocument sourceDocument = PdfDocument.open(sourceTempFile.getPath())) {
+                totalPages = sourceDocument.pageCount();
+                List<stirling.software.jpdfium.doc.Bookmark> roots = sourceDocument.bookmarks();
+                if (roots == null || roots.isEmpty()) {
+                    log.warn("No outline found for {}", file.getOriginalFilename());
+                    throw ExceptionUtils.createIllegalArgumentException(
+                            "error.pdfBookmarksNotFound",
+                            "No PDF bookmarks/outline found in document");
+                }
+                collectBookmarks(roots, bookmarks, 0, bookmarkLevel);
+                if (bookmarks.isEmpty()) {
+                    log.warn("No outline found for {}", file.getOriginalFilename());
+                    throw ExceptionUtils.createIllegalArgumentException(
+                            "error.pdfBookmarksNotFound",
+                            "No PDF bookmarks/outline found in document");
+                }
+                assignEndPages(bookmarks, totalPages);
             }
 
             boolean allowDuplicates = Boolean.TRUE.equals(request.getAllowDuplicates());
             if (!allowDuplicates) {
-                /*
-                duplicates are generated when multiple bookmarks correspond to the same page,
-                if the user doesn't want duplicates mergeBookmarksThatCorrespondToSamePage() method will merge the titles of all
-                the bookmarks that correspond to the same page, and treat them as a single bookmark
-                */
                 bookmarks = mergeBookmarksThatCorrespondToSamePage(bookmarks);
             }
             for (Bookmark bookmark : bookmarks) {
@@ -184,7 +145,15 @@ public class SplitPdfByChaptersController {
                         bookmark.getEndPage());
             }
 
-            TempFile zipTempFile = createZipFile(sourceDocument, bookmarks, includeMetadata);
+            PdfMetadata metadata = null;
+            if (includeMetadata) {
+                try (PDDocument metaDoc = pdfDocumentFactory.load(sourceTempFile.getFile())) {
+                    metadata = pdfMetadataService.extractMetadataFromPdf(metaDoc);
+                }
+            }
+
+            TempFile zipTempFile =
+                    createZipFile(sourceTempFile.getFile(), bookmarks, metadata, totalPages);
             String filename = GeneralUtils.generateFilename(file.getOriginalFilename(), "");
             return WebResponseUtils.zipFileToWebResponse(zipTempFile, filename + ".zip");
         }
@@ -216,45 +185,23 @@ public class SplitPdfByChaptersController {
     }
 
     private TempFile createZipFile(
-            PDDocument sourceDocument, List<Bookmark> bookmarks, boolean includeMetadata)
+            File sourceFile, List<Bookmark> bookmarks, PdfMetadata metadata, int totalPages)
             throws Exception {
-        PdfMetadata metadata =
-                includeMetadata ? pdfMetadataService.extractMetadataFromPdf(sourceDocument) : null;
         String fileNumberFormatter = "%0" + (Integer.toString(bookmarks.size()).length()) + "d ";
         TempFile zipTempFile = new TempFile(tempFileManager, ".zip");
-        try {
-            try (ZipOutputStream zipOut =
-                    new ZipOutputStream(Files.newOutputStream(zipTempFile.getPath()))) {
-                for (int i = 0; i < bookmarks.size(); i++) {
-                    Bookmark bookmark = bookmarks.get(i);
-                    try (PDDocument splitDocument = new PDDocument()) {
-                        boolean isSinglePage = (bookmark.getStartPage() == bookmark.getEndPage());
-
-                        for (int pg = bookmark.getStartPage();
-                                pg < bookmark.getEndPage() + (isSinglePage ? 1 : 0);
-                                pg++) {
-                            PDPage page = sourceDocument.getPage(pg);
-                            splitDocument.addPage(page);
-                            log.debug("Adding page {} to split document", pg);
-                        }
-                        if (includeMetadata) {
-                            pdfMetadataService.setMetadataToPdf(splitDocument, metadata);
-                        }
-
-                        // split files will be named as "[FILE_NUMBER] [BOOKMARK_TITLE].pdf"
-                        String fileName =
-                                String.format(Locale.ROOT, fileNumberFormatter, i)
-                                        + bookmark.getTitle()
-                                        + ".pdf";
-                        zipOut.putNextEntry(new ZipEntry(fileName));
-                        splitDocument.save(zipOut);
-                        zipOut.closeEntry();
-                        log.debug("Wrote split document {} to zip file", fileName);
-                    } catch (Exception e) {
-                        ExceptionUtils.logException("document splitting and saving", e);
-                        throw e;
-                    }
-                }
+        try (PdfDocument sourceDocument = PdfDocument.open(sourceFile.toPath());
+                ZipOutputStream zipOut =
+                        new ZipOutputStream(Files.newOutputStream(zipTempFile.getPath()))) {
+            for (int i = 0; i < bookmarks.size(); i++) {
+                Bookmark bookmark = bookmarks.get(i);
+                writeChapter(
+                        sourceDocument,
+                        bookmark,
+                        i,
+                        fileNumberFormatter,
+                        metadata,
+                        zipOut,
+                        totalPages);
             }
             log.info(
                     "Successfully created zip file with split documents: {}",
@@ -265,6 +212,50 @@ public class SplitPdfByChaptersController {
             throw e;
         }
     }
+
+    private void writeChapter(
+            PdfDocument sourceDocument,
+            Bookmark bookmark,
+            int index,
+            String fileNumberFormatter,
+            PdfMetadata metadata,
+            ZipOutputStream zipOut,
+            int totalPages)
+            throws Exception {
+        boolean isSinglePage = (bookmark.getStartPage() == bookmark.getEndPage());
+        int from = Math.min(Math.max(0, bookmark.getStartPage()), totalPages - 1);
+        int rawEnd = isSinglePage ? bookmark.getEndPage() : bookmark.getEndPage() - 1;
+        int to = Math.min(Math.max(from, rawEnd), totalPages - 1);
+        try (TempFile splitTemp = new TempFile(tempFileManager, ".pdf")) {
+            try (PdfDocument splitDoc = PdfSplit.extractPageRange(sourceDocument, from, to)) {
+                splitDoc.save(splitTemp.getPath());
+            }
+            Path finalPath = splitTemp.getPath();
+            TempFile metaTemp = null;
+            try {
+                if (metadata != null) {
+                    metaTemp = new TempFile(tempFileManager, ".pdf");
+                    try (PDDocument doc = pdfDocumentFactory.load(splitTemp.getFile())) {
+                        pdfMetadataService.setMetadataToPdf(doc, metadata);
+                        doc.save(metaTemp.getFile());
+                    }
+                    finalPath = metaTemp.getPath();
+                }
+                String fileName =
+                        String.format(Locale.ROOT, fileNumberFormatter, index)
+                                + bookmark.getTitle()
+                                + ".pdf";
+                zipOut.putNextEntry(new ZipEntry(fileName));
+                Files.copy(finalPath, zipOut);
+                zipOut.closeEntry();
+                log.debug("Wrote split document {} to zip file", fileName);
+            } finally {
+                if (metaTemp != null) {
+                    metaTemp.close();
+                }
+            }
+        }
+    }
 }
 
 @Data

app/core/src/main/java/stirling/software/SPDF/controller/api/SplitPdfBySizeController.java

@@ -1,19 +1,16 @@
 package stirling.software.SPDF.controller.api;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
 
 import org.apache.pdfbox.pdmodel.PDDocument;
-import org.apache.pdfbox.pdmodel.PDPage;
 import org.springframework.core.io.Resource;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
@@ -37,6 +34,8 @@ import stirling.software.common.util.GeneralUtils;
 import stirling.software.common.util.TempFile;
 import stirling.software.common.util.TempFileManager;
 import stirling.software.common.util.WebResponseUtils;
+import stirling.software.jpdfium.PdfDocument;
+import stirling.software.jpdfium.PdfSplit;
 
 @GeneralApi
 @Slf4j
@@ -75,23 +74,20 @@ public class SplitPdfBySizeController {
                         sourceTempFile.getPath(),
                         StandardCopyOption.REPLACE_EXISTING);
 
-                try (PDDocument sourceDocument =
-                        pdfDocumentFactory.load(sourceTempFile.getFile(), true)) {
-                    boolean hasForm = sourceDocument.getDocumentCatalog().getAcroForm(null) != null;
-                    List<List<Integer>> ranges = computeRanges(request, sourceDocument);
+                boolean hasForm;
+                try (PDDocument acroDoc = pdfDocumentFactory.load(sourceTempFile.getFile(), true)) {
+                    hasForm = acroDoc.getDocumentCatalog().getAcroForm(null) != null;
+                }
+
+                try (PdfDocument sourceDocument = PdfDocument.open(sourceTempFile.getPath())) {
+                    List<int[]> ranges = computeRanges(request, sourceDocument);
 
                     int fileIndex = 1;
-                    for (List<Integer> range : ranges) {
-                        if (range.isEmpty()) {
+                    for (int[] range : ranges) {
+                        if (range.length == 0) {
                             continue;
                         }
-                        if (hasForm) {
-                            writeRangeViaReload(
-                                    sourceTempFile.getFile(), range, zipOut, filename, fileIndex++);
-                        } else {
-                            writeRangeViaSharedSource(
-                                    sourceDocument, range, zipOut, filename, fileIndex++);
-                        }
+                        writeRange(sourceDocument, range, zipOut, filename, fileIndex++, hasForm);
                     }
                 }
             }
@@ -104,80 +100,80 @@ public class SplitPdfBySizeController {
         }
     }
 
-    private List<List<Integer>> computeRanges(
-            SplitPdfBySizeOrCountRequest request, PDDocument sourceDocument) throws IOException {
+    private List<int[]> computeRanges(SplitPdfBySizeOrCountRequest request, PdfDocument sourceDoc)
+            throws IOException {
         int type = request.getSplitType();
         String value = request.getSplitValue();
         if (type == 0) {
-            return computeSizeRanges(sourceDocument, GeneralUtils.convertSizeToBytes(value));
+            return computeSizeRanges(sourceDoc, GeneralUtils.convertSizeToBytes(value));
         } else if (type == 1) {
-            return computePageCountRanges(sourceDocument, Integer.parseInt(value));
+            return computePageCountRanges(sourceDoc, Integer.parseInt(value));
         } else if (type == 2) {
-            return computeDocCountRanges(sourceDocument, Integer.parseInt(value));
+            return computeDocCountRanges(sourceDoc, Integer.parseInt(value));
         }
         throw ExceptionUtils.createIllegalArgumentException(
                 "error.invalidArgument", "Invalid argument: {0}", "split type: " + type);
     }
 
-    private void writeRangeViaReload(
-            File sourceFile,
-            List<Integer> keepIndices,
+    private void writeRange(
+            PdfDocument sourceDoc,
+            int[] range,
             ZipOutputStream zipOut,
             String baseFilename,
-            int fileIndex)
+            int fileIndex,
+            boolean hasForm)
             throws IOException {
-        Set<Integer> keep = new HashSet<>(keepIndices);
-        try (PDDocument doc = pdfDocumentFactory.load(sourceFile)) {
-            for (int i = doc.getNumberOfPages() - 1; i >= 0; i--) {
-                if (!keep.contains(i)) {
-                    doc.removePage(i);
+        try (TempFile splitTemp = new TempFile(tempFileManager, ".pdf")) {
+            extractRangeToFile(sourceDoc, range, splitTemp.getPath());
+            Path finalPath = splitTemp.getPath();
+            TempFile prunedTemp = null;
+            try {
+                if (hasForm) {
+                    prunedTemp = new TempFile(tempFileManager, ".pdf");
+                    try (PDDocument doc = pdfDocumentFactory.load(splitTemp.getFile())) {
+                        FormUtils.pruneOrphanedFormFields(doc);
+                        doc.save(prunedTemp.getFile());
+                    }
+                    finalPath = prunedTemp.getPath();
+                }
+                writeEntry(zipOut, baseFilename, fileIndex, finalPath);
+            } finally {
+                if (prunedTemp != null) {
+                    prunedTemp.close();
                 }
             }
-            FormUtils.pruneOrphanedFormFields(doc);
-            writeEntry(zipOut, baseFilename, fileIndex, doc);
         }
     }
 
-    private void writeRangeViaSharedSource(
-            PDDocument sourceDocument,
-            List<Integer> keepIndices,
-            ZipOutputStream zipOut,
-            String baseFilename,
-            int fileIndex)
+    private void extractRangeToFile(PdfDocument sourceDoc, int[] range, Path outputPath)
             throws IOException {
-        try (PDDocument doc =
-                pdfDocumentFactory.createNewDocumentBasedOnOldDocument(sourceDocument)) {
-            for (int p : keepIndices) {
-                doc.addPage(sourceDocument.getPage(p));
-            }
-            writeEntry(zipOut, baseFilename, fileIndex, doc);
+        int from = range[0];
+        int to = range[range.length - 1];
+        try (PdfDocument split = PdfSplit.extractPageRange(sourceDoc, from, to)) {
+            split.save(outputPath);
         }
     }
 
     private void writeEntry(
-            ZipOutputStream zipOut, String baseFilename, int fileIndex, PDDocument doc)
+            ZipOutputStream zipOut, String baseFilename, int fileIndex, Path pdfPath)
             throws IOException {
         zipOut.putNextEntry(new ZipEntry(baseFilename + "_" + fileIndex + ".pdf"));
-        doc.save(zipOut);
+        Files.copy(pdfPath, zipOut);
         zipOut.closeEntry();
     }
 
-    /** Page-index ranges each output should contain. AcroForm overhead isn't modeled. */
-    private List<List<Integer>> computeSizeRanges(PDDocument sourceDocument, long maxBytes)
-            throws IOException {
-        List<List<Integer>> ranges = new ArrayList<>();
-        List<Integer> currentRange = new ArrayList<>();
-        int totalPages = sourceDocument.getNumberOfPages();
+    /** Returns contiguous page-index ranges fitting within {@code maxBytes}. */
+    private List<int[]> computeSizeRanges(PdfDocument sourceDoc, long maxBytes) throws IOException {
+        List<int[]> ranges = new ArrayList<>();
+        int totalPages = sourceDoc.pageCount();
         int baseCheckFrequency = 5;
-
-        PDDocument scratch = new PDDocument();
-        try {
+        int rangeStart = 0;
+        int rangeEnd = -1;
+        try (TempFile probe = new TempFile(tempFileManager, ".pdf")) {
+            File probeFile = probe.getFile();
             for (int pageIndex = 0; pageIndex < totalPages; pageIndex++) {
-                PDPage page = sourceDocument.getPage(pageIndex);
-                scratch.addPage(new PDPage(page.getCOSObject()));
-                currentRange.add(pageIndex);
-
-                int pageAdded = currentRange.size();
+                rangeEnd = pageIndex;
+                int pageAdded = rangeEnd - rangeStart + 1;
                 boolean shouldCheckSize =
                         (pageAdded % baseCheckFrequency == 0)
                                 || (pageIndex == totalPages - 1)
@@ -185,117 +181,110 @@ public class SplitPdfBySizeController {
                 if (!shouldCheckSize) {
                     continue;
                 }
-
-                long actualSize;
-                try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
-                    scratch.save(out);
-                    actualSize = out.size();
-                }
+                long actualSize = saveRange(sourceDoc, rangeStart, rangeEnd, probeFile);
 
                 if (actualSize > maxBytes) {
-                    if (scratch.getNumberOfPages() > 1) {
-                        scratch.removePage(scratch.getNumberOfPages() - 1);
-                        currentRange.remove(currentRange.size() - 1);
-                        pageIndex--; // retry this page in the next chunk
+                    if (pageAdded > 1) {
+                        rangeEnd = pageIndex - 1;
+                        pageIndex--;
                     }
-                    ranges.add(new ArrayList<>(currentRange));
-                    currentRange.clear();
-                    scratch.close();
-                    scratch = new PDDocument();
+                    ranges.add(buildRange(rangeStart, rangeEnd));
+                    rangeStart = rangeEnd + 1;
+                    rangeEnd = rangeStart - 1;
                 } else if (pageIndex < totalPages - 1 && actualSize < maxBytes * 0.75) {
-                    int extraPagesAdded =
-                            lookAheadFit(scratch, sourceDocument, pageIndex, maxBytes);
-                    for (int i = 0; i < extraPagesAdded; i++) {
-                        int extra = pageIndex + 1 + i;
-                        scratch.addPage(new PDPage(sourceDocument.getPage(extra).getCOSObject()));
-                        currentRange.add(extra);
-                    }
-                    pageIndex += extraPagesAdded;
+                    int extra =
+                            lookAheadFit(
+                                    sourceDoc,
+                                    rangeStart,
+                                    pageIndex,
+                                    maxBytes,
+                                    totalPages,
+                                    probeFile);
+                    pageIndex += extra;
+                    rangeEnd = pageIndex;
                 }
             }
-
-            if (!currentRange.isEmpty()) {
-                ranges.add(new ArrayList<>(currentRange));
-            }
-        } finally {
-            scratch.close();
+        }
+        if (rangeEnd >= rangeStart) {
+            ranges.add(buildRange(rangeStart, rangeEnd));
         }
         return ranges;
     }
 
-    /** Speculatively tries up to 5 next pages; returns how many fit under {@code maxBytes}. */
-    private int lookAheadFit(PDDocument scratch, PDDocument source, int pageIndex, long maxBytes)
+    private long saveRange(PdfDocument sourceDoc, int from, int to, File output)
             throws IOException {
-        int totalPages = source.getNumberOfPages();
-        int pagesToLookAhead = Math.min(5, totalPages - pageIndex - 1);
-        if (pagesToLookAhead == 0) {
-            return 0;
+        try (PdfDocument split = PdfSplit.extractPageRange(sourceDoc, from, to)) {
+            split.save(output.toPath());
         }
-
-        int extraPagesAdded = 0;
-        try (PDDocument testDoc = new PDDocument()) {
-            for (int i = 0; i < scratch.getNumberOfPages(); i++) {
-                testDoc.addPage(new PDPage(scratch.getPage(i).getCOSObject()));
-            }
-            for (int i = 0; i < pagesToLookAhead; i++) {
-                testDoc.addPage(new PDPage(source.getPage(pageIndex + 1 + i).getCOSObject()));
-                long testSize;
-                try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
-                    testDoc.save(out);
-                    testSize = out.size();
-                }
-                if (testSize > maxBytes) {
-                    break;
-                }
-                extraPagesAdded++;
-            }
-        }
-        return extraPagesAdded;
+        return output.length();
     }
 
-    private List<List<Integer>> computePageCountRanges(PDDocument sourceDocument, int pageCount) {
+    private int lookAheadFit(
+            PdfDocument sourceDoc,
+            int rangeStart,
+            int currentEnd,
+            long maxBytes,
+            int totalPages,
+            File probeFile)
+            throws IOException {
+        int pagesToLookAhead = Math.min(5, totalPages - currentEnd - 1);
+        int extra = 0;
+        for (int i = 0; i < pagesToLookAhead; i++) {
+            int trialEnd = currentEnd + 1 + i;
+            long size = saveRange(sourceDoc, rangeStart, trialEnd, probeFile);
+            if (size > maxBytes) {
+                break;
+            }
+            extra++;
+        }
+        return extra;
+    }
+
+    private List<int[]> computePageCountRanges(PdfDocument sourceDoc, int pageCount) {
         if (pageCount <= 0) {
             throw ExceptionUtils.createIllegalArgumentException(
                     "error.invalidArgument", "Invalid argument: {0}", "page count: " + pageCount);
         }
-        int totalPages = sourceDocument.getNumberOfPages();
-        List<List<Integer>> ranges = new ArrayList<>();
-        List<Integer> current = new ArrayList<>(pageCount);
-        for (int i = 0; i < totalPages; i++) {
-            current.add(i);
-            if (current.size() == pageCount) {
-                ranges.add(current);
-                current = new ArrayList<>(pageCount);
-            }
-        }
-        if (!current.isEmpty()) {
-            ranges.add(current);
+        int totalPages = sourceDoc.pageCount();
+        List<int[]> ranges = new ArrayList<>();
+        int start = 0;
+        while (start < totalPages) {
+            int end = Math.min(start + pageCount - 1, totalPages - 1);
+            ranges.add(buildRange(start, end));
+            start = end + 1;
         }
         return ranges;
     }
 
-    private List<List<Integer>> computeDocCountRanges(
-            PDDocument sourceDocument, int documentCount) {
+    private List<int[]> computeDocCountRanges(PdfDocument sourceDoc, int documentCount) {
         if (documentCount <= 0) {
             throw ExceptionUtils.createIllegalArgumentException(
                     "error.invalidArgument",
                     "Invalid argument: {0}",
                     "document count: " + documentCount);
         }
-        int totalPages = sourceDocument.getNumberOfPages();
+        int totalPages = sourceDoc.pageCount();
         int pagesPerDocument = totalPages / documentCount;
         int extraPages = totalPages % documentCount;
-
-        List<List<Integer>> ranges = new ArrayList<>();
+        List<int[]> ranges = new ArrayList<>();
         int cursor = 0;
         for (int i = 0; i < documentCount; i++) {
             int pagesToAdd = pagesPerDocument + (i < extraPages ? 1 : 0);
-            List<Integer> range = new ArrayList<>(pagesToAdd);
-            for (int j = 0; j < pagesToAdd; j++) {
-                range.add(cursor++);
+            if (pagesToAdd == 0) {
+                continue;
             }
-            ranges.add(range);
+            int end = cursor + pagesToAdd - 1;
+            ranges.add(buildRange(cursor, end));
+            cursor = end + 1;
         }
         return ranges;
     }
+
+    private static int[] buildRange(int start, int end) {
+        int[] range = new int[end - start + 1];
+        for (int i = 0; i < range.length; i++) {
+            range[i] = start + i;
+        }
+        return range;
+    }
 }

app/core/src/test/java/stirling/software/SPDF/bench/SplitBenchmark.java

@@ -0,0 +1,365 @@
+package stirling.software.SPDF.bench;
+
+import java.awt.Color;
+import java.awt.Font;
+import java.awt.Graphics2D;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.lang.management.MemoryMXBean;
+import java.lang.management.MemoryUsage;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+
+import javax.imageio.ImageIO;
+
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.font.PDType1Font;
+import org.apache.pdfbox.pdmodel.font.Standard14Fonts;
+import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
+import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationWidget;
+import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
+import org.apache.pdfbox.pdmodel.interactive.form.PDTextField;
+import org.junit.jupiter.api.Test;
+
+import stirling.software.common.util.FormUtils;
+import stirling.software.jpdfium.PdfDocument;
+import stirling.software.jpdfium.PdfSplit;
+
+/**
+ * Apples-to-apples heap + wall-clock benchmark for split: legacy PDFBox path (load + addPage per
+ * range + save) vs JPDFium path (PdfSplit.extractPageRange + save).
+ *
+ * <p>Generates a single ~N-page PDF with one JPEG per page, then performs a "split into chunks of
+ * 10" run with both backends. Samples heap every 25 ms during execution.
+ *
+ * <p>Run only when explicitly requested: -Dsplit.bench=true
+ */
+public final class SplitBenchmark {
+
+    private static final int PAGES = Integer.getInteger("split.bench.pages", 100);
+    private static final int CHUNK = Integer.getInteger("split.bench.chunk", 10);
+    private static final int IMAGE_W = Integer.getInteger("split.bench.imgW", 800);
+    private static final int IMAGE_H = Integer.getInteger("split.bench.imgH", 600);
+    private static final long SAMPLE_PERIOD_MS = 25L;
+
+    @Test
+    void compareSplitMemoryFootprint() throws Exception {
+        if (!Boolean.getBoolean("split.bench")) {
+            System.out.println("Skipping SplitBenchmark (run with -Dsplit.bench=true)");
+            return;
+        }
+        main(new String[0]);
+    }
+
+    public static void main(String[] args) throws Exception {
+        Path workDir = Files.createTempDirectory("split-bench-");
+        System.out.println("Work dir: " + workDir);
+        System.out.printf(
+                "Generating %d-page input PDF with %dx%d images per page...%n",
+                PAGES, IMAGE_W, IMAGE_H);
+
+        Path input = workDir.resolve("input.pdf");
+        long t0 = System.nanoTime();
+        generateTestPdf(input, PAGES);
+        long buildMs = (System.nanoTime() - t0) / 1_000_000;
+        System.out.printf(
+                "  built %s: %,d KB (%d pages) in %,d ms%n%n",
+                input.getFileName(), Files.size(input) / 1024, PAGES, buildMs);
+
+        // Warmup - prime classloaders, JIT, native lib.
+        System.out.println("--- Warmup (results discarded) ---");
+        runPdfBoxSplit(input, workDir.resolve("warmup-pdfbox"), CHUNK);
+        runJpdfiumSplit(input, workDir.resolve("warmup-jpdfium"), CHUNK);
+        forceGcQuiescence();
+        System.out.println();
+
+        long baseline = sampleUsedHeapAfterGc();
+        System.out.printf("Baseline heap (after GC, before split): %,d KB%n%n", baseline / 1024);
+
+        // PDFBox run
+        System.out.println("--- PDFBox split (load + addPage + save per chunk) ---");
+        Path outBoxDir = workDir.resolve("out-pdfbox");
+        BenchResult pdfboxResult = profile(() -> runPdfBoxSplit(input, outBoxDir, CHUNK));
+        pdfboxResult.printSummary("PDFBox", baseline);
+
+        forceGcQuiescence();
+        System.out.println();
+
+        // JPDFium run
+        System.out.println("--- JPDFium split (PdfSplit.extractPageRange + save) ---");
+        Path outJpdDir = workDir.resolve("out-jpdfium");
+        BenchResult jpdfiumResult = profile(() -> runJpdfiumSplit(input, outJpdDir, CHUNK));
+        jpdfiumResult.printSummary("JPDFium", baseline);
+
+        // Compare
+        System.out.println();
+        System.out.println("=== Heap delta over baseline ===");
+        long pdfboxDelta = pdfboxResult.peakHeapBytes - baseline;
+        long jpdfiumDelta = jpdfiumResult.peakHeapBytes - baseline;
+        double improvement =
+                pdfboxDelta == 0 ? 0.0 : (100.0 * (pdfboxDelta - jpdfiumDelta) / pdfboxDelta);
+        System.out.printf("  PDFBox  : +%,d KB%n", pdfboxDelta / 1024);
+        System.out.printf("  JPDFium : +%,d KB%n", jpdfiumDelta / 1024);
+        System.out.printf("  JPDFium uses %.1f%% LESS heap than PDFBox%n", improvement);
+
+        System.out.println();
+        System.out.println("=== Wall-clock ===");
+        System.out.printf("  PDFBox  : %,d ms%n", pdfboxResult.wallMs);
+        System.out.printf("  JPDFium : %,d ms%n", jpdfiumResult.wallMs);
+        double speedup =
+                jpdfiumResult.wallMs == 0
+                        ? 0.0
+                        : ((double) pdfboxResult.wallMs / jpdfiumResult.wallMs);
+        System.out.printf("  Speedup : %.2fx%n", speedup);
+
+        // Hybrid form-pruning sub-benchmark.
+        // Quantifies the heap re-introduced by the PDFBox post-pass that
+        // pruneOrphanedFormFields runs on each JPDFium-produced split.
+        System.out.println();
+        System.out.println("=== Hybrid form-pruning sub-benchmark ===");
+        Path formInput = workDir.resolve("form-input.pdf");
+        generateFormPdf(formInput, PAGES);
+        System.out.printf(
+                "  built %s with AcroForm: %,d KB (%d pages)%n",
+                formInput.getFileName(), Files.size(formInput) / 1024, PAGES);
+
+        runJpdfiumSplit(formInput, workDir.resolve("warmup-form-bare"), CHUNK);
+        runJpdfiumSplitWithFormPrune(formInput, workDir.resolve("warmup-form-pruned"), CHUNK);
+        forceGcQuiescence();
+
+        BenchResult bareForm =
+                profile(() -> runJpdfiumSplit(formInput, workDir.resolve("out-form-bare"), CHUNK));
+        bareForm.printSummary("JPDFium-only", sampleUsedHeapAfterGc());
+
+        forceGcQuiescence();
+        BenchResult prunedForm =
+                profile(
+                        () ->
+                                runJpdfiumSplitWithFormPrune(
+                                        formInput, workDir.resolve("out-form-pruned"), CHUNK));
+        prunedForm.printSummary("JPDFium+PDFBox-prune", sampleUsedHeapAfterGc());
+
+        long pruneOverhead = prunedForm.peakHeapBytes - bareForm.peakHeapBytes;
+        long pruneTimeOverhead = prunedForm.wallMs - bareForm.wallMs;
+        System.out.printf(
+                "  Hybrid prune overhead: +%,d KB heap, +%,d ms wall (%.1fx slower)%n",
+                pruneOverhead / 1024,
+                pruneTimeOverhead,
+                bareForm.wallMs == 0 ? 0.0 : (double) prunedForm.wallMs / bareForm.wallMs);
+    }
+
+    private static void runJpdfiumSplitWithFormPrune(Path input, Path outDir, int chunk)
+            throws IOException {
+        Files.createDirectories(outDir);
+        try (PdfDocument source = PdfDocument.open(input)) {
+            int total = source.pageCount();
+            int index = 0;
+            for (int start = 0; start < total; start += chunk) {
+                int end = Math.min(start + chunk - 1, total - 1);
+                Path raw = outDir.resolve("raw-" + (index + 1) + ".pdf");
+                try (PdfDocument split = PdfSplit.extractPageRange(source, start, end)) {
+                    split.save(raw);
+                }
+                Path pruned = outDir.resolve("pruned-" + (++index) + ".pdf");
+                try (PDDocument doc = org.apache.pdfbox.Loader.loadPDF(raw.toFile())) {
+                    FormUtils.pruneOrphanedFormFields(doc);
+                    doc.save(pruned.toFile());
+                }
+                Files.deleteIfExists(raw);
+            }
+        }
+    }
+
+    private static void generateFormPdf(Path out, int pages) throws IOException {
+        try (PDDocument doc = new PDDocument()) {
+            for (int i = 0; i < pages; i++) {
+                PDPage page = new PDPage(PDRectangle.A4);
+                doc.addPage(page);
+            }
+            PDAcroForm acroForm = new PDAcroForm(doc);
+            doc.getDocumentCatalog().setAcroForm(acroForm);
+            // One text field per page (orphan-prone scenario).
+            for (int i = 0; i < pages; i++) {
+                PDTextField field = new PDTextField(acroForm);
+                field.setPartialName("field_" + i);
+                acroForm.getFields().add(field);
+                PDAnnotationWidget widget = new PDAnnotationWidget();
+                widget.setRectangle(new PDRectangle(50, 50, 200, 30));
+                widget.setPage(doc.getPage(i));
+                doc.getPage(i).getAnnotations().add(widget);
+                field.getWidgets().add(widget);
+            }
+            doc.save(out.toFile());
+        }
+    }
+
+    private static void runPdfBoxSplit(Path input, Path outDir, int chunk) throws IOException {
+        Files.createDirectories(outDir);
+        try (PDDocument source = org.apache.pdfbox.Loader.loadPDF(input.toFile())) {
+            int total = source.getNumberOfPages();
+            int index = 0;
+            for (int start = 0; start < total; start += chunk) {
+                int end = Math.min(start + chunk - 1, total - 1);
+                Set<Integer> keep = new HashSet<>();
+                for (int p = start; p <= end; p++) keep.add(p);
+                // Match the pre-jpdfium reload path: load fresh, removePage, save.
+                try (PDDocument split = org.apache.pdfbox.Loader.loadPDF(input.toFile())) {
+                    for (int p = split.getNumberOfPages() - 1; p >= 0; p--) {
+                        if (!keep.contains(p)) split.removePage(p);
+                    }
+                    split.save(outDir.resolve("split-" + (++index) + ".pdf").toFile());
+                }
+            }
+        }
+    }
+
+    private static void runJpdfiumSplit(Path input, Path outDir, int chunk) throws IOException {
+        Files.createDirectories(outDir);
+        try (PdfDocument source = PdfDocument.open(input)) {
+            int total = source.pageCount();
+            int index = 0;
+            for (int start = 0; start < total; start += chunk) {
+                int end = Math.min(start + chunk - 1, total - 1);
+                try (PdfDocument split = PdfSplit.extractPageRange(source, start, end)) {
+                    split.save(outDir.resolve("split-" + (++index) + ".pdf"));
+                }
+            }
+        }
+    }
+
+    private static void generateTestPdf(Path out, int pages) throws IOException {
+        try (PDDocument doc = new PDDocument()) {
+            Random rng = new Random(42L);
+            for (int i = 0; i < pages; i++) {
+                PDPage page = new PDPage(PDRectangle.A4);
+                doc.addPage(page);
+
+                byte[] jpegBytes = generateRandomJpeg(rng, IMAGE_W, IMAGE_H);
+                PDImageXObject xobj = PDImageXObject.createFromByteArray(doc, jpegBytes, "img");
+
+                try (PDPageContentStream cs =
+                        new PDPageContentStream(
+                                doc, page, PDPageContentStream.AppendMode.APPEND, false)) {
+                    float pageW = page.getMediaBox().getWidth();
+                    float pageH = page.getMediaBox().getHeight();
+                    float imgW = pageW - 100;
+                    float imgH = imgW * IMAGE_H / IMAGE_W;
+                    float x = (pageW - imgW) / 2;
+                    float y = pageH - 80 - imgH;
+                    cs.drawImage(xobj, x, y, imgW, imgH);
+                    cs.beginText();
+                    cs.setFont(new PDType1Font(Standard14Fonts.FontName.HELVETICA), 14);
+                    cs.newLineAtOffset(50, 30);
+                    cs.showText("Page " + (i + 1) + " bench fill");
+                    cs.endText();
+                }
+            }
+            doc.save(out.toFile());
+        }
+    }
+
+    private static byte[] generateRandomJpeg(Random rng, int w, int h) throws IOException {
+        BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
+        Graphics2D g = img.createGraphics();
+        try {
+            float hue = rng.nextFloat();
+            g.setColor(Color.getHSBColor(hue, 0.4f, 0.95f));
+            g.fillRect(0, 0, w, h);
+            for (int i = 0; i < 20; i++) {
+                g.setColor(Color.getHSBColor(rng.nextFloat(), 0.6f, 0.5f + rng.nextFloat() * 0.5f));
+                int r = 20 + rng.nextInt(80);
+                int cx = rng.nextInt(w);
+                int cy = rng.nextInt(h);
+                g.fillOval(cx - r, cy - r, r * 2, r * 2);
+            }
+            g.setColor(Color.BLACK);
+            g.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 32));
+            g.drawString("bench image", 40, h - 40);
+        } finally {
+            g.dispose();
+        }
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ImageIO.write(img, "jpg", baos);
+        return baos.toByteArray();
+    }
+
+    private static BenchResult profile(ThrowingRunnable task) throws Exception {
+        forceGcQuiescence();
+        MemoryMXBean mem = ManagementFactory.getMemoryMXBean();
+        AtomicLong peakHeap = new AtomicLong(0);
+        AtomicLong peakNonHeap = new AtomicLong(0);
+        AtomicBoolean stop = new AtomicBoolean(false);
+
+        Thread sampler =
+                new Thread(
+                        () -> {
+                            while (!stop.get()) {
+                                MemoryUsage heap = mem.getHeapMemoryUsage();
+                                MemoryUsage nonHeap = mem.getNonHeapMemoryUsage();
+                                peakHeap.updateAndGet(p -> Math.max(p, heap.getUsed()));
+                                peakNonHeap.updateAndGet(p -> Math.max(p, nonHeap.getUsed()));
+                                try {
+                                    Thread.sleep(SAMPLE_PERIOD_MS);
+                                } catch (InterruptedException e) {
+                                    Thread.currentThread().interrupt();
+                                    return;
+                                }
+                            }
+                        },
+                        "split-bench-sampler");
+        sampler.setDaemon(true);
+        sampler.start();
+
+        long t0 = System.nanoTime();
+        try {
+            task.run();
+        } finally {
+            stop.set(true);
+            sampler.join();
+        }
+        long wallMs = (System.nanoTime() - t0) / 1_000_000;
+        return new BenchResult(peakHeap.get(), peakNonHeap.get(), wallMs);
+    }
+
+    private static void forceGcQuiescence() {
+        for (int i = 0; i < 3; i++) {
+            System.gc();
+            try {
+                Thread.sleep(50);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                return;
+            }
+        }
+    }
+
+    private static long sampleUsedHeapAfterGc() {
+        forceGcQuiescence();
+        return ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
+    }
+
+    @FunctionalInterface
+    interface ThrowingRunnable {
+        void run() throws Exception;
+    }
+
+    private record BenchResult(long peakHeapBytes, long peakNonHeapBytes, long wallMs) {
+        void printSummary(String label, long baselineBytes) {
+            System.out.printf(
+                    "  %s peak heap    : %,d KB (delta over baseline: +%,d KB)%n",
+                    label, peakHeapBytes / 1024, (peakHeapBytes - baselineBytes) / 1024);
+            System.out.printf("  %s peak nonHeap : %,d KB%n", label, peakNonHeapBytes / 1024);
+            System.out.printf("  %s wall-clock   : %,d ms%n", label, wallMs);
+        }
+    }
+}

app/core/src/test/java/stirling/software/SPDF/controller/api/SplitPDFControllerTest.java

@@ -4,17 +4,25 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.lenient;
 import static org.mockito.Mockito.when;
 
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
 
 import org.apache.pdfbox.Loader;
 import org.apache.pdfbox.pdmodel.PDDocument;
 import org.apache.pdfbox.pdmodel.PDPage;
 import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
+import org.apache.pdfbox.pdmodel.interactive.form.PDTextField;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
@@ -23,8 +31,12 @@ import org.junit.jupiter.api.io.TempDir;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+import org.mockito.junit.jupiter.MockitoSettings;
+import org.mockito.quality.Strictness;
+import org.springframework.core.io.Resource;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 import org.springframework.mock.web.MockMultipartFile;
 
 import stirling.software.SPDF.model.api.SplitPagesRequest;
@@ -32,6 +44,7 @@ import stirling.software.common.service.CustomPDFDocumentFactory;
 import stirling.software.common.util.TempFileManager;
 
 @ExtendWith(MockitoExtension.class)
+@MockitoSettings(strictness = Strictness.LENIENT)
 class SplitPDFControllerTest {
 
     @TempDir Path tempDir;
@@ -47,6 +60,12 @@ class SplitPDFControllerTest {
                             String suffix = invocation.getArgument(0);
                             return Files.createTempFile(tempDir, "test", suffix).toFile();
                         });
+        lenient()
+                .when(pdfDocumentFactory.load(any(File.class), eq(true)))
+                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
+        lenient()
+                .when(pdfDocumentFactory.load(any(File.class)))
+                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
     }
 
     private byte[] createPdf(int numPages) throws IOException {
@@ -60,17 +79,47 @@ class SplitPDFControllerTest {
         }
     }
 
-    private void setupFactory() throws IOException {
-        when(pdfDocumentFactory.load(any(File.class), eq(true)))
-                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
-        when(pdfDocumentFactory.load(any(File.class)))
-                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
-        when(pdfDocumentFactory.createNewDocumentBasedOnOldDocument(any(PDDocument.class)))
-                .thenAnswer(inv -> new PDDocument());
+    private byte[] createPdfWithForm(int numPages) throws IOException {
+        try (PDDocument doc = new PDDocument()) {
+            for (int i = 0; i < numPages; i++) {
+                doc.addPage(new PDPage(PDRectangle.A4));
+            }
+            PDAcroForm acroForm = new PDAcroForm(doc);
+            doc.getDocumentCatalog().setAcroForm(acroForm);
+            PDTextField field = new PDTextField(acroForm);
+            field.setPartialName("testField");
+            acroForm.getFields().add(field);
+            Path pdfPath = tempDir.resolve("input.pdf");
+            doc.save(pdfPath.toFile());
+            return Files.readAllBytes(pdfPath);
+        }
+    }
+
+    private List<byte[]> unzip(Resource zipResource) throws IOException {
+        List<byte[]> entries = new ArrayList<>();
+        try (ZipInputStream zis =
+                new ZipInputStream(new ByteArrayInputStream(zipResource.getContentAsByteArray()))) {
+            ZipEntry entry;
+            while ((entry = zis.getNextEntry()) != null) {
+                entries.add(zis.readAllBytes());
+                zis.closeEntry();
+            }
+        }
+        return entries;
+    }
+
+    private int[] pageCountsOf(List<byte[]> entries) throws IOException {
+        int[] counts = new int[entries.size()];
+        for (int i = 0; i < entries.size(); i++) {
+            try (PDDocument doc = Loader.loadPDF(entries.get(i))) {
+                counts[i] = doc.getNumberOfPages();
+            }
+        }
+        return counts;
     }
 
     @Test
-    @DisplayName("Should split 6-page PDF at page 3")
+    @DisplayName("Should split 6-page PDF at page 3 into 2 parts")
     void shouldSplitAtPage3() throws Exception {
         byte[] pdfBytes = createPdf(6);
         MockMultipartFile file =
@@ -81,11 +130,12 @@ class SplitPDFControllerTest {
         request.setFileInput(file);
         request.setPageNumbers("3");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(2);
+        assertThat(pageCountsOf(outputs)).containsExactly(3, 3);
     }
 
     @Test
@@ -100,11 +150,12 @@ class SplitPDFControllerTest {
         request.setFileInput(file);
         request.setPageNumbers("1,2,3");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(pageCountsOf(outputs)).containsExactly(1, 1, 1);
     }
 
     @Test
@@ -119,15 +170,16 @@ class SplitPDFControllerTest {
         request.setFileInput(file);
         request.setPageNumbers("1");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(1);
+        assertThat(pageCountsOf(outputs)).containsExactly(1);
     }
 
     @Test
-    @DisplayName("Should split with range notation")
+    @DisplayName("Should split with multiple split points")
     void shouldSplitWithRange() throws Exception {
         byte[] pdfBytes = createPdf(10);
         MockMultipartFile file =
@@ -138,11 +190,12 @@ class SplitPDFControllerTest {
         request.setFileInput(file);
         request.setPageNumbers("3,7");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(pageCountsOf(outputs)).containsExactly(3, 4, 3);
     }
 
     @Test
@@ -157,13 +210,14 @@ class SplitPDFControllerTest {
         request.setFileInput(file);
         request.setPageNumbers("2");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
         assertThat(response.getHeaders().getContentType())
                 .isEqualTo(MediaType.APPLICATION_OCTET_STREAM);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(2);
+        assertThat(pageCountsOf(outputs)).containsExactly(2, 2);
     }
 
     @Test
@@ -178,11 +232,12 @@ class SplitPDFControllerTest {
         request.setFileInput(file);
         request.setPageNumbers("5");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(1);
+        assertThat(pageCountsOf(outputs)).containsExactly(5);
     }
 
     @Test
@@ -197,29 +252,31 @@ class SplitPDFControllerTest {
         request.setFileInput(file);
         request.setPageNumbers("all");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(pageCountsOf(outputs)).containsExactly(1, 1, 1);
     }
 
     @Test
-    @DisplayName("Should handle file without extension in original name")
-    void shouldHandleFileWithoutExtension() throws Exception {
-        byte[] pdfBytes = createPdf(2);
+    @DisplayName("Should split PDF with form fields and keep form-aware path")
+    void shouldSplitFormPdf() throws Exception {
+        byte[] pdfBytes = createPdfWithForm(4);
         MockMultipartFile file =
                 new MockMultipartFile(
-                        "fileInput", "no_extension", MediaType.APPLICATION_PDF_VALUE, pdfBytes);
+                        "fileInput", "input.pdf", MediaType.APPLICATION_PDF_VALUE, pdfBytes);
 
         SplitPagesRequest request = new SplitPagesRequest();
         request.setFileInput(file);
-        request.setPageNumbers("1");
+        request.setPageNumbers("2");
 
-        setupFactory();
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(2);
+        assertThat(pageCountsOf(outputs)).containsExactly(2, 2);
     }
 }

app/core/src/test/java/stirling/software/SPDF/controller/api/SplitPdfByChaptersControllerTest.java

@@ -4,11 +4,18 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.lenient;
 import static org.mockito.Mockito.when;
 
+import java.io.ByteArrayInputStream;
+import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
 
 import org.apache.pdfbox.Loader;
 import org.apache.pdfbox.pdmodel.PDDocument;
@@ -27,10 +34,11 @@ import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
+import org.springframework.core.io.Resource;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 import org.springframework.mock.web.MockMultipartFile;
-import org.springframework.web.multipart.MultipartFile;
 
 import stirling.software.SPDF.model.api.SplitPdfByChaptersRequest;
 import stirling.software.common.service.CustomPDFDocumentFactory;
@@ -55,6 +63,9 @@ class SplitPdfByChaptersControllerTest {
                             String suffix = inv.getArgument(0);
                             return Files.createTempFile(tempDir, "test", suffix).toFile();
                         });
+        lenient()
+                .when(pdfDocumentFactory.load(any(File.class)))
+                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
     }
 
     private byte[] createPdfWithBookmarks(int numPages, String... chapterNames) throws IOException {
@@ -83,6 +94,29 @@ class SplitPdfByChaptersControllerTest {
         }
     }
 
+    private List<byte[]> unzip(Resource zipResource) throws IOException {
+        List<byte[]> entries = new ArrayList<>();
+        try (ZipInputStream zis =
+                new ZipInputStream(new ByteArrayInputStream(zipResource.getContentAsByteArray()))) {
+            ZipEntry entry;
+            while ((entry = zis.getNextEntry()) != null) {
+                entries.add(zis.readAllBytes());
+                zis.closeEntry();
+            }
+        }
+        return entries;
+    }
+
+    private int totalPagesOf(List<byte[]> entries) throws IOException {
+        int total = 0;
+        for (byte[] data : entries) {
+            try (PDDocument doc = Loader.loadPDF(data)) {
+                total += doc.getNumberOfPages();
+            }
+        }
+        return total;
+    }
+
     @Test
     @DisplayName("Should split PDF by chapters")
     void shouldSplitByChapters() throws Exception {
@@ -97,12 +131,12 @@ class SplitPdfByChaptersControllerTest {
         request.setIncludeMetadata(false);
         request.setAllowDuplicates(false);
 
-        when(pdfDocumentFactory.load(any(MultipartFile.class)))
-                .thenAnswer(inv -> Loader.loadPDF(((MultipartFile) inv.getArgument(0)).getBytes()));
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(totalPagesOf(outputs)).isEqualTo(6);
     }
 
     @Test
@@ -119,12 +153,12 @@ class SplitPdfByChaptersControllerTest {
         request.setIncludeMetadata(false);
         request.setAllowDuplicates(true);
 
-        when(pdfDocumentFactory.load(any(MultipartFile.class)))
-                .thenAnswer(inv -> Loader.loadPDF(((MultipartFile) inv.getArgument(0)).getBytes()));
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(2);
+        assertThat(totalPagesOf(outputs)).isEqualTo(4);
     }
 
     @Test
@@ -163,10 +197,6 @@ class SplitPdfByChaptersControllerTest {
             request.setIncludeMetadata(false);
             request.setAllowDuplicates(false);
 
-            when(pdfDocumentFactory.load(any(MultipartFile.class)))
-                    .thenAnswer(
-                            inv -> Loader.loadPDF(((MultipartFile) inv.getArgument(0)).getBytes()));
-
             assertThrows(IllegalArgumentException.class, () -> controller.splitPdf(request));
         }
     }
@@ -185,12 +215,12 @@ class SplitPdfByChaptersControllerTest {
         request.setIncludeMetadata(false);
         request.setAllowDuplicates(false);
 
-        when(pdfDocumentFactory.load(any(MultipartFile.class)))
-                .thenAnswer(inv -> Loader.loadPDF(((MultipartFile) inv.getArgument(0)).getBytes()));
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(1);
+        assertThat(totalPagesOf(outputs)).isEqualTo(3);
     }
 
     @Test
@@ -207,14 +237,15 @@ class SplitPdfByChaptersControllerTest {
         request.setIncludeMetadata(true);
         request.setAllowDuplicates(false);
 
-        when(pdfDocumentFactory.load(any(MultipartFile.class)))
-                .thenAnswer(inv -> Loader.loadPDF(((MultipartFile) inv.getArgument(0)).getBytes()));
-        when(pdfMetadataService.extractMetadataFromPdf(any(PDDocument.class)))
+        lenient()
+                .when(pdfMetadataService.extractMetadataFromPdf(any(PDDocument.class)))
                 .thenReturn(new stirling.software.common.model.PdfMetadata());
 
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(totalPagesOf(outputs)).isEqualTo(4);
     }
 
     @Test
@@ -231,12 +262,12 @@ class SplitPdfByChaptersControllerTest {
         request.setIncludeMetadata(false);
         request.setAllowDuplicates(false);
 
-        when(pdfDocumentFactory.load(any(MultipartFile.class)))
-                .thenAnswer(inv -> Loader.loadPDF(((MultipartFile) inv.getArgument(0)).getBytes()));
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(totalPagesOf(outputs)).isEqualTo(6);
     }
 
     @Test
@@ -253,11 +284,11 @@ class SplitPdfByChaptersControllerTest {
         request.setIncludeMetadata(false);
         request.setAllowDuplicates(true);
 
-        when(pdfDocumentFactory.load(any(MultipartFile.class)))
-                .thenAnswer(inv -> Loader.loadPDF(((MultipartFile) inv.getArgument(0)).getBytes()));
-
-        var response = controller.splitPdf(request);
+        ResponseEntity<Resource> response = controller.splitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(5);
+        assertThat(totalPagesOf(outputs)).isEqualTo(10);
     }
 }

app/core/src/test/java/stirling/software/SPDF/controller/api/SplitPdfBySizeControllerTest.java

@@ -4,12 +4,18 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.lenient;
 import static org.mockito.Mockito.when;
 
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
 
 import org.apache.pdfbox.Loader;
 import org.apache.pdfbox.pdmodel.PDDocument;
@@ -23,6 +29,9 @@ import org.junit.jupiter.api.io.TempDir;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+import org.mockito.junit.jupiter.MockitoSettings;
+import org.mockito.quality.Strictness;
+import org.springframework.core.io.Resource;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
@@ -33,6 +42,7 @@ import stirling.software.common.service.CustomPDFDocumentFactory;
 import stirling.software.common.util.TempFileManager;
 
 @ExtendWith(MockitoExtension.class)
+@MockitoSettings(strictness = Strictness.LENIENT)
 class SplitPdfBySizeControllerTest {
 
     @TempDir Path tempDir;
@@ -48,69 +58,131 @@ class SplitPdfBySizeControllerTest {
                             String suffix = invocation.getArgument(0);
                             return Files.createTempFile(tempDir, "test", suffix).toFile();
                         });
+        lenient()
+                .when(pdfDocumentFactory.load(any(File.class), eq(true)))
+                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
+        lenient()
+                .when(pdfDocumentFactory.load(any(File.class)))
+                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
     }
 
-    @Test
-    @DisplayName("Should split by page count successfully")
-    void shouldSplitByPageCount() throws Exception {
-        byte[] pdfBytes;
+    private byte[] createPdf(int numPages) throws IOException {
         try (PDDocument doc = new PDDocument()) {
-            for (int i = 0; i < 5; i++) {
+            for (int i = 0; i < numPages; i++) {
                 doc.addPage(new PDPage(PDRectangle.A4));
             }
             Path pdfPath = tempDir.resolve("input.pdf");
             doc.save(pdfPath.toFile());
-            pdfBytes = Files.readAllBytes(pdfPath);
+            return Files.readAllBytes(pdfPath);
         }
+    }
 
+    private List<byte[]> unzip(Resource zipResource) throws IOException {
+        List<byte[]> entries = new ArrayList<>();
+        try (ZipInputStream zis =
+                new ZipInputStream(new ByteArrayInputStream(zipResource.getContentAsByteArray()))) {
+            ZipEntry entry;
+            while ((entry = zis.getNextEntry()) != null) {
+                entries.add(zis.readAllBytes());
+                zis.closeEntry();
+            }
+        }
+        return entries;
+    }
+
+    private int[] pageCountsOf(List<byte[]> entries) throws IOException {
+        int[] counts = new int[entries.size()];
+        for (int i = 0; i < entries.size(); i++) {
+            try (PDDocument doc = Loader.loadPDF(entries.get(i))) {
+                counts[i] = doc.getNumberOfPages();
+            }
+        }
+        return counts;
+    }
+
+    @Test
+    @DisplayName("Should split by page count into 2-page chunks")
+    void shouldSplitByPageCount() throws Exception {
+        byte[] pdfBytes = createPdf(5);
         MockMultipartFile file =
                 new MockMultipartFile(
                         "fileInput", "input.pdf", MediaType.APPLICATION_PDF_VALUE, pdfBytes);
         SplitPdfBySizeOrCountRequest request = new SplitPdfBySizeOrCountRequest();
         request.setFileInput(file);
-        request.setSplitType(1); // Page count
+        request.setSplitType(1);
         request.setSplitValue("2");
 
-        when(pdfDocumentFactory.load(any(File.class), eq(true)))
-                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
-        when(pdfDocumentFactory.createNewDocumentBasedOnOldDocument(any(PDDocument.class)))
-                .thenAnswer(inv -> new PDDocument());
-
-        ResponseEntity<?> response = controller.autoSplitPdf(request);
+        ResponseEntity<Resource> response = controller.autoSplitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
         assertThat(response.getHeaders().getContentType())
                 .isEqualTo(MediaType.APPLICATION_OCTET_STREAM);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(pageCountsOf(outputs)).containsExactly(2, 2, 1);
     }
 
     @Test
-    @DisplayName("Should split by document count successfully")
+    @DisplayName("Should split by document count into 3 even documents")
     void shouldSplitByDocCount() throws Exception {
-        byte[] pdfBytes;
-        try (PDDocument doc = new PDDocument()) {
-            for (int i = 0; i < 6; i++) {
-                doc.addPage(new PDPage(PDRectangle.A4));
-            }
-            Path pdfPath = tempDir.resolve("input.pdf");
-            doc.save(pdfPath.toFile());
-            pdfBytes = Files.readAllBytes(pdfPath);
-        }
-
+        byte[] pdfBytes = createPdf(6);
         MockMultipartFile file =
                 new MockMultipartFile(
                         "fileInput", "input.pdf", MediaType.APPLICATION_PDF_VALUE, pdfBytes);
         SplitPdfBySizeOrCountRequest request = new SplitPdfBySizeOrCountRequest();
         request.setFileInput(file);
-        request.setSplitType(2); // Document count
-        request.setSplitValue("3"); // Split into 3 docs (2 pages each)
+        request.setSplitType(2);
+        request.setSplitValue("3");
 
-        when(pdfDocumentFactory.load(any(File.class), eq(true)))
-                .thenAnswer(inv -> Loader.loadPDF((File) inv.getArgument(0)));
-        when(pdfDocumentFactory.createNewDocumentBasedOnOldDocument(any(PDDocument.class)))
-                .thenAnswer(inv -> new PDDocument());
-
-        ResponseEntity<?> response = controller.autoSplitPdf(request);
+        ResponseEntity<Resource> response = controller.autoSplitPdf(request);
 
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(pageCountsOf(outputs)).containsExactly(2, 2, 2);
+    }
+
+    @Test
+    @DisplayName("Should split by document count distributing extras")
+    void shouldSplitByDocCountWithRemainder() throws Exception {
+        byte[] pdfBytes = createPdf(7);
+        MockMultipartFile file =
+                new MockMultipartFile(
+                        "fileInput", "input.pdf", MediaType.APPLICATION_PDF_VALUE, pdfBytes);
+        SplitPdfBySizeOrCountRequest request = new SplitPdfBySizeOrCountRequest();
+        request.setFileInput(file);
+        request.setSplitType(2);
+        request.setSplitValue("3");
+
+        ResponseEntity<Resource> response = controller.autoSplitPdf(request);
+
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).hasSize(3);
+        assertThat(pageCountsOf(outputs)).containsExactly(3, 2, 2);
+    }
+
+    @Test
+    @DisplayName("Should split by size into multiple files")
+    void shouldSplitBySize() throws Exception {
+        byte[] pdfBytes = createPdf(20);
+        MockMultipartFile file =
+                new MockMultipartFile(
+                        "fileInput", "input.pdf", MediaType.APPLICATION_PDF_VALUE, pdfBytes);
+        SplitPdfBySizeOrCountRequest request = new SplitPdfBySizeOrCountRequest();
+        request.setFileInput(file);
+        request.setSplitType(0);
+        request.setSplitValue("3KB");
+
+        ResponseEntity<Resource> response = controller.autoSplitPdf(request);
+
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+        List<byte[]> outputs = unzip(response.getBody());
+        assertThat(outputs).isNotEmpty();
+        int total = 0;
+        for (int count : pageCountsOf(outputs)) {
+            total += count;
+        }
+        assertThat(total).isEqualTo(20);
     }
 }