Use of method parameters in Java se learning

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The Java programming language does not use reference calls to objects, in fact, object references are Value Passing .

In the Java programming language, the use of method parameters:

1, a method can't Modify the parameters of a basic data type (i.e. numeric and Boolean);

2, a method can change the state of an object parameter;

3. A method cannot be implemented so that the object argument references a new object.

Here is the test code

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Package Se;public class Paramtest {/** * <p> * </p> * @author Zhangjunshuai * @date 2014-10-29 Morning 10:42:39 * @p Aram args */public static void main (string[] args) {///1, Experiment one SYSTEM.OUT.PRINTLN ("Testing Triplevalue");d ouble percent = 10; System.out.println ("before:percent=" +percent); Triplevalue (percent); System.out.println ("after:percent=" +percent);//2, Experiment two System.out.println ("\ntesting triplevalue Object"); StringBuffer percentd = new StringBuffer ("Start ——————"); System.out.println ("before:percent=" +percentd); Triplevalue (PERCENTD); System.out.println ("after:percent=" +percentd);//2.1, experiment two test string Object System.out.println ("\ntesting triplevalue Object "); String percents = "string start ——————"; System.out.println ("before:percent=" +percents); Triplevalue (percents); System.out.println ("after:percent=" +percents);//3, Experiment 3system.out.println ("\ntesting triplesalary:"); Employee Harry = new Employee ("Harry", 50000); System.out.println ("before:salary=" +harry.getsalary ()); Triplesalary (Harry); System.out.println ("AfteR:salary= "+harry.getsalary ()),//4, experimental 4system.out.println (" \ntesting swap: "); Employee A = new Employee ("Alice", 7000); Employee B = New Employee ("Bob", 6000); System.out.println ("before:a=" +a.getname ()); System.out.println ("before:b=" +b.getname ()), swap (A, b); System.out.println ("after:a=" +a.getname ()); System.out.println ("after:b=" +b.getname ());} A method cannot modify a string, public static void Triplevalue (String x) {x = x+ ("test"); System.out.println ("End of method:x =" +x);} public static void Triplevalue (StringBuffer x) {x = x.append ("test"); System.out.println ("End of method:x =" +x);} A method cannot modify the parameters of a base data type public static void Triplevalue (double x) {x = 3 * x; System.out.println ("End of method:x =" +x);} A method can change the state of an object parameter public static void Triplesalary (Employee x) {x.raisesalary (200); System.out.println ("End of Method:x=" +x.getsalary ());} A method cannot be implemented so that the object argument references a new object public static void swap (Employee x,employee y) {System.out.println ("before of method:x=" + X.getname ()); System.out.println ("Before of Method:y=" +y.getname ()); EmPloyee temp = x;x= Y;y = temp; System.out.println ("End of Method:x=" +x.getname ()); System.out.println ("End of Method:y=" +y.getname ());}} Class Employee {private string name;private double salary;public Employee (String n,double s) {name = N;salary = S;} public void Raisesalary (double i) {double raise = salary*i/100;salary + = Raise;} Public String GetName () {return name;} public void SetName (String name) {this.name = name;} Public double getsalary () {return salary;} public void Setsalary (double salary) {this.salary = salary;}}

Use of method parameters in Java se learning