Constructor Detail

• DirectMemoryUtils

  public DirectMemoryUtils()

Method Detail

• getDirectMemorySize

  public static long getDirectMemorySize()

  Returns:

  the setting of -XX:MaxDirectMemorySize as a long. Returns 0 if -XX:MaxDirectMemorySize is not set.

• getDirectMemoryUsage

  public static long getDirectMemoryUsage()

  Returns:

  the current amount of direct memory used.

• destroyDirectByteBuffer

  public static void destroyDirectByteBuffer(ByteBuffer toBeDestroyed)
                                      throws IllegalArgumentException,
                                             IllegalAccessException,
                                             InvocationTargetException,
                                             SecurityException,
                                             NoSuchMethodException

  DirectByteBuffers are garbage collected by using a phantom reference and a reference queue. Every once a while, the JVM checks the reference queue and cleans the DirectByteBuffers. However, as this doesn't happen immediately after discarding all references to a DirectByteBuffer, it's easy to OutOfMemoryError yourself using DirectByteBuffers. This function explicitly calls the Cleaner method of a DirectByteBuffer.

  Parameters:

  toBeDestroyed - The DirectByteBuffer that will be "cleaned". Utilizes reflection.

  Throws:

  IllegalArgumentException

  IllegalAccessException

  InvocationTargetException

  SecurityException

  NoSuchMethodException