小编ياس*_*حمد的帖子

this在Java中使用关键字optional吗？或者我必须使用它吗？当它不是可选的？在下面的代码中,它不会影响我的应用程序,无论Employee我做了多少个实例.print即使细节不匹配,该方法也会打印员工详细信息而不会出现任何问题.

public class Employee {
    String name;
    int Salary;
    int pension;
    String workPlace;
    String teleNo;
    int age;

    void printDetails(){
        System.out.println("Name is :  "+this.name );
        System.out.println("age is  :  "+this.age );
        System.out.println("WorkPlace is  :  "+this.workPlace );
        System.out.println("Salary is  :  "+Salary );
        System.out.println("Pension is  :  "+this.pension );
        System.out.println("Telephone No. is  :  "+this.teleNo );
        System.out.println("age is  :  "+Integer.toString(age) );
    }
}

public class Main extends Employee {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Employee …