Program: 91978
Project: 91978
Buggy source:
/** 
 * Returns the grid of the given name. This method returns the cached instance if it still exists, or load the grid otherwise.
 * @param latitudeShifts   Name of the grid file for latitude shifts.
 * @param longitudeShifts  Name of the grid file for longitude shifts.
 */
static DatumShiftGridFile<Angle,Angle> getOrLoad(final Path latitudeShifts,final Path longitudeShifts) throws FactoryException {
  final Path rlat=DataDirectory.DATUM_CHANGES.resolve(latitudeShifts).toAbsolutePath();
  final Path rlon=DataDirectory.DATUM_CHANGES.resolve(longitudeShifts).toAbsolutePath();
  final Object key=new AbstractMap.SimpleImmutableEntry<>(rlat,rlon);
  DatumShiftGridFile<?,?> grid=DatumShiftGridFile.CACHE.peek(key);
  if (grid == null) {
    final Cache.Handler<DatumShiftGridFile<?,?>> handler=DatumShiftGridFile.CACHE.lock(key);
    try {
      grid=handler.peek();
      if (grid == null) {
        final Loader loader;
        Path file=latitudeShifts;
        try {
          final ByteBuffer buffer=ByteBuffer.allocate(4096).order(ByteOrder.LITTLE_ENDIAN);
          final FloatBuffer fb=buffer.asFloatBuffer();
          try (final ReadableByteChannel in=Files.newByteChannel(rlat)){
            DatumShiftGridLoader.log(NADCON.class,CharSequences.commonPrefix(latitudeShifts.toString(),longitudeShifts.toString()).toString() + '…');
            loader=new Loader(in,buffer,file);
            loader.readGrid(fb,null,longitudeShifts);
          }
           buffer.clear();
          file=longitudeShifts;
          try (final ReadableByteChannel in=Files.newByteChannel(rlon)){
            new Loader(in,buffer,file).readGrid(fb,loader,null);
          }
         }
 catch (        IOException|NoninvertibleTransformException|RuntimeException e) {
          throw new FactoryException(Errors.format(Errors.Keys.CanNotParseFile_2,"String_Node_Str",file),e);
        }
        grid=DatumShiftGridCompressed.compress(loader.grid,null,loader.grid.accuracy);
        grid=grid.useSharedData();
      }
    }
  finally {
      handler.putAndUnlock(grid);
    }
  }
  return grid.castTo(Angle.class,Angle.class);
}

Fixed version (ground truth):
/** 
 * Returns the grid of the given name. This method returns the cached instance if it still exists, or load the grid otherwise.
 * @param latitudeShifts   Name of the grid file for latitude shifts.
 * @param longitudeShifts  Name of the grid file for longitude shifts.
 */
@SuppressWarnings("String_Node_Str") static DatumShiftGridFile<Angle,Angle> getOrLoad(final Path latitudeShifts,final Path longitudeShifts) throws FactoryException {
  final Path rlat=DataDirectory.DATUM_CHANGES.resolve(latitudeShifts).toAbsolutePath();
  final Path rlon=DataDirectory.DATUM_CHANGES.resolve(longitudeShifts).toAbsolutePath();
  final Object key=new AbstractMap.SimpleImmutableEntry<>(rlat,rlon);
  DatumShiftGridFile<?,?> grid=DatumShiftGridFile.CACHE.peek(key);
  if (grid == null) {
    final Cache.Handler<DatumShiftGridFile<?,?>> handler=DatumShiftGridFile.CACHE.lock(key);
    try {
      grid=handler.peek();
      if (grid == null) {
        final Loader loader;
        Path file=latitudeShifts;
        try {
          final ByteBuffer buffer=ByteBuffer.allocate(4096).order(ByteOrder.LITTLE_ENDIAN);
          final FloatBuffer fb=buffer.asFloatBuffer();
          try (final ReadableByteChannel in=Files.newByteChannel(rlat)){
            DatumShiftGridLoader.log(NADCON.class,CharSequences.commonPrefix(latitudeShifts.toString(),longitudeShifts.toString()).toString() + '…');
            loader=new Loader(in,buffer,file);
            loader.readGrid(fb,null,longitudeShifts);
          }
           buffer.clear();
          file=longitudeShifts;
          try (final ReadableByteChannel in=Files.newByteChannel(rlon)){
            new Loader(in,buffer,file).readGrid(fb,loader,null);
          }
         }
 catch (        IOException|NoninvertibleTransformException|RuntimeException e) {
          final String message=Errors.format(Errors.Keys.CanNotParseFile_2,"String_Node_Str",file);
          if (e instanceof NoSuchFileException) {
            throw new MissingFactoryResourceException(message,e);
          }
 else {
            throw new FactoryDataException(message,e);
          }
        }
        grid=DatumShiftGridCompressed.compress(loader.grid,null,loader.grid.accuracy);
        grid=grid.useSharedData();
      }
    }
  finally {
      handler.putAndUnlock(grid);
    }
  }
  return grid.castTo(Angle.class,Angle.class);
}