Findbugs has flagged some code in the file

src/share/classes/sun/net/www/protocol/jar/URLJarFile.java

as potentially not closing its streams. Specifically, the code
opens streams 'in' and 'out' and attempts to close them in a finally
block at line 236:

    } finally {
        if (in != null) {
            in.close();
        }
        if (out != null) {
            out.close();
        }
    }

Unfortunately, if in.close() were to throw an exception, this might
leave out unclosed. There are a few other similar problems as well.

This code can be cleaned up using the new Java 7 try-with-resources
construct. It can also take advantage of the new Files utility method
for copying from a stream to a file.