Java OOP; creating several objects

Question

I am trying to store students' data in main class, in the student class I did the following:

public class Student {
        public static String name = "UNKNOWN";
        Student(){

        }

        Student(String name) {
            this.name = name;}

While in main I did the following:

public class Main {

    public static void main (String[] args) {
        //s1 is short for student1
        Student s1 = new Student ("Chris");
        Student s2 = new Student ("Layla");
        Student s3 = new Student ("Mark");

This issue is, whenever I print a sx.name I'd always print the last one. So for the following code:

System.out.println(s1.name);

I'd get Mark, while it should be Chris.

Just remove static keyword in name field

Uzair
– Uzair

2021-05-07 00:49:49 +00:00
Commented May 7, 2021 at 0:49 — Uzair
– Uzair, Commented May 7, 2021 at 0:49

Yati Sawhney - Yates · Accepted Answer · 2021-05-07 00:42:07Z

Yes, Because static fields are shared by all the objects. Please change your code as follows:

public class Student {
        public String name;
        Student(){

        }

        Student(String name) {
            this.name = name;

}

public static void main (String[] args) {
        //s1 is short for student1
        Student s1 = new Student ("Chris");
        Student s2 = new Student ("Layla");
        Student s3 = new Student ("Mark");
}

When to use static in java?

Sometimes, you want to have variables that are common to all objects. This is accomplished with the static modifier. Fields that have the static modifier in their declaration are called static fields or class variables. They are associated with the class, rather than with any object. Every instance of the class shares a class variable, which is in one fixed location in memory. Any object can change the value of a class variable, but class variables can also be manipulated without creating an instance of the class.

lisz1012 · Accepted Answer · 2021-05-07 02:47:25Z

0

The static variable name is accessed by instances, which is not recommended in Java. You can make it non-static. The IDE, such as IDEA, will give you some hint/warning about this issue, like:

So with the help of IDEs, you can easily find some potential issues.

answered May 7, 2021 at 2:47

lisz1012

213 bronze badges

Collectives™ on Stack Overflow

Java OOP; creating several objects

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related