Hibernate4 + c3p0 + Derby - Memory Leak on Tomcat stop or web application reload

Question

I have a very simple application template which includes an embedded apache derby database through hibernate.

I have the following configuration:

Answer 1

After doing some more research I found that closing explicitely all the connections solves the issue:

C3P0Registry.getNumPooledDataSources();

@SuppressWarnings({ "unchecked", "rawtypes" })
Iterator<Set> it = C3P0Registry.getPooledDataSources().iterator();
while (it.hasNext()) {
    try {
           dataSource = (PooledDataSource) it.next();
           dataSource.close();
    } catch (Exception e) {
           logger.error(e);
    }
}

Answer 2

A more concise version of the accepted answer that did the trick for me

for (Object o : C3P0Registry.getPooledDataSources()) {
  try {
    ((PooledDataSource) o).close();
  } catch (Exception e) {
    // oh well, let tomcat do the complaing for us.
  }
}