CCNA, CCNP, MCSA, CCNA Final Exam, All Answer Test Module With 100/100

I want to join stderr ( getErrorStream ) and stdout ( getInputStream ) of a Process into a single Stream to be consumed elsewhere. Is there anything in Java's library that will do that for me? Note: no external libraries . I'm not interested in the existence of a solution provided by, say, Apache Commons IO. I only want to know if there's something that comes with JDK.