code: public void addSourceFolder(File sourceFolder) throws ApkCreationException, SealedApkException,
              DuplicateFileException {
          if (mIsSealed) {
              throw new SealedApkException("APK is already sealed");
          }
  
          addSourceFolder(this, sourceFolder);
      }
docs: Adds the resources from a source folder.
  @param sourceFolder the source folder.
  @throws ApkCreationException if an error occurred
  @throws SealedApkException if the APK is already sealed.
  @throws DuplicateFileException if a file conflicts with another already added to the APK
  at the same location inside the APK archive.