How to garbage collect a direct buffer in Java

Question

I have a memory leak that I have isolated to incorrectly disposed direct byte buffers.

ByteBuffer buff = ByteBuffer.allocateDirect(7777777);

The GC colle

Answer 1

Here is a refined implementation that will work for any direct buffer:

public static void destroyBuffer(Buffer buffer) {
    if(buffer.isDirect()) {
        try {
            if(!buffer.getClass().getName().equals("java.nio.DirectByteBuffer")) {
                Field attField = buffer.getClass().getDeclaredField("att");
                attField.setAccessible(true);
                buffer = (Buffer) attField.get(buffer);
            }

            Method cleanerMethod = buffer.getClass().getMethod("cleaner");
            cleanerMethod.setAccessible(true);
            Object cleaner = cleanerMethod.invoke(buffer);
            Method cleanMethod = cleaner.getClass().getMethod("clean");
            cleanMethod.setAccessible(true);
            cleanMethod.invoke(cleaner);
        } catch(Exception e) {
            throw new QuartetRuntimeException("Could not destroy direct buffer " + buffer, e);
        }
    }
}