Java Basics-Programs are executed sequentially

class   testa{        publicstaticvoid  main (string[] args)     {        String AA = "AAA";        String bb= "bbb" +AA;        AA= "CCCC";        System.out.println (BB);    }}

The output is "bbbaaa

class   testa{        publicstaticvoid  main (string[] args)     {        String AA = "AAA";        String bb= "BBB";        AA= "CCCC";        System.out.println (BB+aa);}    }

The output is BBBCCC

The program is sequential execution, from top to bottom execution, this small foundation, the most basic thing suppressed me half a day ah.

Java Basics-Programs are executed sequentially