How to remove unused objects from a PDF file (Tutorial)

PDF files sometimes contain objects which are never used. This increases the file size and is wasteful. This tutorial shows you how to reduce the file size by removing these unused objects in Java or using the command line.
 
The PDF file format is not natively supported by Java, so to remove unused objects from a PDF file you will need to download an external library. This tutorial uses JPedal.
 

How to remove unwanted objects from a PDF file programmatically

1. Add JPedal to your class or module path (download the trial jar)
2. Create a File handle pointing to the PDF file
3. Run the below code:
   

   PdfOptimizer.optimizePDF(
   
           new File("/path/to/input.pdf"),
   
           new File("/path/to/output.pdf"),
   
           PdfOptimizer.Optimization.REMOVEUNUSEDOBJECTS
   
   );
   
   

How to remove unwanted objects from a PDF file using the command line

1. Download the JPedal trial jar
2. Run the following command:
   

   java -cp jpedal.jar org.jpedal.tools.PdfOptimizer --removeUnusedObjects inputFile outputFile
   
   

   
   

Viewer viewer = new Viewer();
viewer.setupViewer();
viewer.executeCommand(ViewerCommands.OPENFILE, "pdfFile.pdf");

//Convenience static method (see class for additional options)
ExtractClippedImages.writeAllClippedImagesToDir("inputFileOrDirectory", "outputDir", "outputImageFormat", new String[] {"imageHeightAsFloat", "subDirectoryForHeight"});

//Convenience static method (see class for additional options)
ExtractTextAsWordList.writeAllWordlistsToDir("inputFileOrDirectory", "outputDir", -1);

//Convenience static method (see class for additional options)
ArrayList resultsForPages = FindTextInRectangle.findTextOnAllPages("/path/to/file.pdf", "textToFind");

PrintPdfPages print = new PrintPdfPages("C:/pdfs/mypdf.pdf");

if (print.openPDFFile()) {
    print.printAllPages("Printer Name");
}

//Convenience static method (see class for additional options)
ExtractClippedImages.writeAllClippedImagesToDir("inputFileOrDirectory", "outputDir", "outputImageFormat", new String[] {"imageHeightAsFloat", "subDirectoryForHeight"});