The most effective way to handle these kind of errors in Java unfortunately requires understanding class loading, thread contexts, wrapping connection primitives in the right kind of references, and then making sure that all resource deallocation/closing always use the same codepath. Even though you really only need to implemnt it once, it is both somewhat tricky and technically challenging.

It's a pity that so few Java projects have tried to use these mechanisms without building them as part of massive frameworks, sometimes apparently even without understanding what they have built.