/** * Uses internal JDK APIs to allocate a DirectByteBuffer while ignoring the JVM's * MaxDirectMemorySize limit (the default limit is too low and we do not want to require users * to increase it). */ @SuppressWarnings("unchecked") public static ByteBuffer allocateDirectBuffer(int size) { try { Class cls = Class.forName("java.nio.DirectByteBuffer"); Constructor constructor = cls.getDeclaredConstructor(Long.TYPE, Integer.TYPE); constructor.setAccessible(true); Field cleanerField = cls.getDeclaredField("cleaner"); cleanerField.setAccessible(true); final long memory = allocateMemory(size); ByteBuffer buffer = (ByteBuffer) constructor.newInstance(memory, size); Cleaner cleaner = Cleaner.create(buffer, new Runnable() { @Override public void run() { freeMemory(memory); } }); cleanerField.set(buffer, cleaner); return buffer; } catch (Exception e) { throwException(e); } throw new IllegalStateException("unreachable"); }