JAVA是值传递，并不是引用传递

值传递是方法得到所有参数的拷贝，方法不能修改传递给它的任何参数变脸的内容。
引用传递是方法得到的是对象引用的拷贝，对象引用及其他的拷贝同时引用同一个对象（类型C++中的指针）

public class passByValue {
    public static void main(String[] args) {

        // 方法值作为参数传递
        double percent =10;
        tripleValue(percent);
        System.out.println("percent:"+percent);

        // 方法引用对象值作为参数传递
        Employee employee = new Employee();
        tripleSalary(employee);
        System.out.println(employee.getSalary());

        // 验证java是不是引用传递，如果是则交换成功，否则失败
        Employee a = new Employee("a",200);
        Employee b = new Employee("b",300);
        swap(a,b);
        System.out.println("a:"+a.toString());
        System.out.println("b:"+b.toString());

    }

    public static void tripleValue(double x) {
        x = 3 * x;
    }

    public static void tripleSalary(Employee x){
        x.tripleSalry(200);

    }

    public static void swap(Employee x,Employee y){
        Employee temp = x;
        y= temp;
        x = y;
    }
}

class Employee{
    private  String name ;
    private double salary;

    public void tripleSalry(double salary){
        this.salary = salary * 3;
    }

    public Employee(double salary) {
        this.salary = salary;
    }

    public Employee(String name, double salary) {
        this.name = name;
        this.salary = salary;
    }

    public Employee() {
    }

    public String getName() {
        return name;
    }

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "name='" + name + '\'' +
                ", salary=" + salary +
                '}';
    }
}

// 值传递不会改变参数的值
percent:10.0
// 引用对象
600.0
//swap结果为失败
a:Employee{name='a', salary=200.0}
b:Employee{name='b', salary=300.0}

结论：Java对对象采用的不是引用传递，而是值传递