Java process memory usage keeps increasing infinitely

Question

Preconditions:

• PC with 16 Gb of RAM
• JDK 1.8.x installed on Ubuntu 16.10 x64.
• a standard Spring-based web application, that is deployed on Tomcat

Answer 1

Can you rerun your tests with this option -XX:MaxDirectMemorySize=1024m? The exact value of this limit does not matter, but it shows possible "leaks".

Can you also provide GC details (-XX:+PrintGC)?

java.nio.ByteBuffer is a possible cause of them due to it specific finalization.

UPDATE #1

I have seen similar behavior for two another reasons: java.misc.Unsafe (unlikely) and high-loaded JNI-calls.

It is hard to understand without profile of the test.

UPDATE #2

Both high-loaded JNI-calls and finalize() method cause the described problem since objects do not have enough time to finalize.

The j.u.zip.Inflater fragment below:

/**
 * Closes the decompressor when garbage is collected.
 */
protected void finalize() {
    end();
}

/**
 * Closes the decompressor and discards any unprocessed input.
 * This method should be called when the decompressor is no longer
 * being used, but will also be called automatically by the finalize()
 * method. Once this method is called, the behavior of the Inflater
 * object is undefined.
 */
public void end() {
    synchronized (zsRef) {
        long addr = zsRef.address();
        zsRef.clear();
        if (addr != 0) {
            end(addr);
            buf = null;
        }
    }
}

private native static void end(long addr);