Memory Leak and OutOfMemoryException - Java Swing 应用程序

Question

I am currently working a Standalone Java Swing application, which is quite a complex one with lot of labels and input text fields. What I found is, after each operation the memory consumption of the application as in Windows Task manager is increasing atleast by 2 MB. Upon reaching to a total memory consumption of ~305 MB, the application crashes with Out of Memory Exception. I explicitly mentioned for garbage collection in the event handler, but it didn't made any good. I profiled the application with JVisualVM. I found few of my classes have a memory graph of an increment slope which never comes down.

But for other classes the graph is quite normal like a wave pattern, as below image:

From above chart I came to conclusion that memory leak is happening for InspectableInputTextImpl class. To fix I added weakReference instantiation for the said class like below:

InspectableInputTextImpl inputText = new InspectableInputTextImpl(screen, componentId, length);
        WeakReference<InspectableInputTextImpl> weakInputText = new WeakReference<InspectableInputTextImpl>(inputText);
        ((TInputText) weakInputText.get()).setCustomDocument(new TRestrict4InputTextDocument());
        ((TInputText) weakInputText.get()).setMaxLength(maxLength);
        ((TInputText) weakInputText.get()).setRequirement(required);

Even this also didn't improved anything, still the memory chart looks exactly same. Below are my questions:

1. Am I correct on the conclusion that InspectableInputTextImpl itself is causing the memory leak based on the chart?

2. If I am correct could you share with your thoughts on fixing the issue. Will converting the instance to a singleton will fix it?

Answer 1

I would suggest analysing a heap dump to verify the cause of memory leak. You can start your application with -XX:+HeapDumpOnOutOfMemoryError VM option and it will create a.hprof file with a dump of the heap at the point it crashes. Then you can use a tool like Eclipse MAT to have a look at the dump. It may verify your suspicion about InspectableInputTextImpl or give you a different clue.

You can take on how to fix the problem (your question 2) after you verify what exactly is the problem (your question 1).