is memory leak? why java.lang.ref.Finalizer eat so much memory

Question

I ran a heap dump on my program. When I opened it in the memory analyzer tool, I found that the java.lang.ref.Finalizer for org.logicalcobwebs.proxool.Pr

Answer 1

From what I can make out, Proxool is a connection pool for JDBC connections. This suggests to me that the problem is that your application is is misusing the connection pool. Instead of calling close on the statement objects, your code is probably dropping them and/or their parent connections. The Proxool is relying on finalizers to close the underlying driver-implemented objects ... but this requires those Finalizer instances. It could also mean that you are causing the connection to open / close (real) database connections more frequently than is necessary, and that would be bad for performance.

So I suggest that you check your code for leaked ResultSet, Statement and/or Connection objects, and make sure that you close them in finally blocks.

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Looking at the memory dump, I expect you are concerned where the 898,527,228 bytes are going. The vast majority are retained by the Finalizer object whose id is 2aab07855e38. If you still have the dump file, take a look at what that Finalizer is referring to. It looks more problematic than the Proxool objects.