JAVA中的参数按值传递与按引用传递

 1 public class TempTest{
 2     private void test1(int a) {
 3         a++;
 4         System.out.println("The char A in test1 method value is :" + a);
 5     }
 6 
 7     public static void main(String[] args) {
 8         TempTest t = new TempTest();
 9         int a = 3;
10         t.test1(a);
11         System.out.println("The char A in main method value is :" + a);
12     }
13 }

 1 public class TempTest1 {
 2     private void test1(A a) {
 3         a.age = 20;
 4         System.out.println("The age in test1 method value is :" + a.age);
 5     }
 6 
 7     public static void main(String[] args) {
 8         TempTest1 t = new TempTest1();
 9         A a = new A();
10         a.age = 10;
11         t.test1(a);
12         System.out.println("The age in main method value is :" + a.age);
13     }
14 }
15 class A {
16     public int age = 0;
17 }

 1 public class TempTest2 {
 2     private void test2(A a) {
 3         a = new A();
 4         a.age = 20;
 5         System.out.println("The age in test2 method value is :" + a.age);
 6     }
 7 
 8     public static void main(String[] args) {
 9         TempTest2 t = new TempTest2();
10         A a = new A();
11         a.age = 10;
12         t.test2(a);
13         System.out.println("The age in main method value is :" + a.age);
14     }
15 }
16 class A {
17     public int age = 0;
18 }