Log4jProxy in commons-logging fork throws NPE if TCCL is null

The Log4jProxy class in the JCL fork has this:

ClassLoader loader = Thread.currentThread().getContextClassLoader();
// Validate that TCL can actually see the log4j classes
try
{
Class levelClass = loader.loadClass("org.apache.log4j.Level");
...
}
catch(ClassNotFoundException e)
{
// No, hack to fall back to this class' class loader
loader = Log4jProxy.class.getClassLoader();
}

This throws an NPE if the TCCL is null.

On a recent case a finalize() method ended up trying to instantiate a logger; failed because the Finalizer thread didn't have a TCCL set.