关于java输出的一道题

static void (int a, int b) {
    System.setOut(new PrintStream(System.out) {
        
        public void println(String x) {
            if (x != null) {
                if (x.equals("a=10")) {
                    x = "a=100,";
                    super.print(x);
                } else {
                    if (x.equals("b=10")) {
                        x = "b=200";
                    }
                    super.println(x);
                }
            } else {
                super.println(x);
            }
        }
    });
}