question: create a callable that always returns null . concode_field_sep IThrowingRunnable m_aRunnable concode_elem_sep DATATYPE m_aResult concode_field_sep DATATYPE call concode_elem_sep String toString
target: AdapterThrowingRunnableToCallable < Object > function ( @ Nonnull final IThrowingRunnable arg0 ) { return new AdapterThrowingRunnableToCallable < Object > ( arg0 ) ; }