New runtimes work differently and are not well tested yet for memory leaks. We are working on fixing issues anything we find.

• When a java object is finally freed in Java, we notify the JS side to free the JS counterpart. At this time, the Java object is held weakly in Java too using a WeakReference. While the Java object is weakly held, the WeakReference is strongly kept in a HashMap never getting removed. In this PR we release the WeakReferences too on GC event ensuring that all memory is reclaimed. Fixed in 5e48302
• Investigate Java Interface Implementation leaking on JS Side