JDK and JRE

Good evening Ladies and Gentlemen:

    JDK(java development kit ),it must be needed when programmers develop java programs. And JDK contains JRE.

    JRE(java runtime environment).it must be needed when java program runs in someone's computer.

    So,a java programmer's computer must install the JDK, and not a professional java programmer's computer install the JRE is enough.

    The knowledge is too easy to read by someone , but that is what I study cannily.

                                                                                                                                       Phoegon Zhou