Resource Leak (Resource out of scope)

Question

Hi here are a couple of lines in the code.

UserAccountVO fun() {
  // ...
  ObjectInputStream in = xstream.createObjectInputStream(is);
  return (UserAccountVO)in.readObject();
}

Now its giving the following warning:

leaked_resource: Variable in going out of scope leaks the resource it refers to".

Can anyone please explain it?

This is how I got it fixed:

try(ObjectInputStream in = xstream.createObjectInputStream(is);) {
  return (UserAccountVO)in.readObject();
} catch (IOException e) {
  s_logger.error(e.getMessage());
  return null;
}

Answer 1

In former case, you are not closing the resource 'in' and that may result in memory leak. Therefore you get a warning. While in later case, you have put the 'in' instantiation within the TRY block which actually adds an implicit 'finally' for you to close the resource.

Hope it clarifies.