code: public void pushClassLoader(BeanMetaData bmd)
      {
          ClassLoader classLoader = bmd.ivContextClassLoader; // F85059
          Object origCL = svThreadContextAccessor.pushContextClassLoaderForUnprivileged(classLoader);
          ivClassLoaderStack.push(origCL);
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
              Tr.debug(tc, "pushClassLoader: " +
                           (origCL == ThreadContextAccessor.UNCHANGED ?
                                           "already " + Util.identity(classLoader) :
                                           Util.identity(origCL) + " -> " + Util.identity(classLoader)));
      }
docs: Sets the thread context class loader for the specified bean metadata, and
  saves the current thread context class loader.