按值传参

看以下代码：

public class anzhichuancan {
    public static void main(String[] args) {
    int num1=1;int num2=2;
    System.out.println("Before invoking the swap method,num1 is"+num1+"and num2 is"+num2);
    swap(num1,num2);
    System.out.println("After invoking the swap method,num1 is"+num1+"and num2 is"+num2);
    }
public static void swap(int n1,int n2) {
    System.out.println("\tInside the swap method");
    System.out.println("\t\tBefore swapping,n1 is"+n1+"and n2 is"+n2);
    int temp=n1;
    n1=n2;
    n2=temp;
    System.out.println("\t\tAfter swapping,n1 is"+n1+"and n2 is"+n2);
}
}

其运行结果如下：

Before invoking the swap method,num1 is1and num2 is2
    Inside the swap method
        Before swapping,n1 is1and n2 is2
        After swapping,n1 is2and n2 is1
After invoking the swap method,num1 is1and num2 is2

这是因为n1和n2有自己独立与num1和num2的存储空间，n1和n2的改变不影响num1和num2的内容。