code: public <T, EXTYPE extends Exception> T readLockedThrowing (@Nonnull final IThrowingSupplier <? extends T, EXTYPE> aCallable) throws EXTYPE
    {
      readLock ().lock ();
      try
      {
        return aCallable.get ();
      }
      finally
      {
        readLock ().unlock ();
      }
    }
docs: Execute the provided callable in a read lock. Note: no
  nullable/non-nullable can be assumed.
  
  @param aCallable
  Callable to be executed. May not be <code>null</code>.
  @return The return value of the callable. May be <code>null</code>.
  @throws EXTYPE
  If the callable throws the exception
  @param <T>
  Return type
  @param <EXTYPE>
  Exception type to be thrown