Static Variable Unwanted

Question

A very simple question for the experts, but for a beginner like me, it is just confusing. I thought I understood Static, but apparently I do not. This below is the entire class, and it says I need to make test static. But I don't want to. What can I do to fix this, and why is it happening in the first place? Thanks!

public class SubstringTest
{
    private String test;

    public static void main(String[] args)
    {
        test = "Penguin";
        System.out.println(test);
        System.out.println(test.substring(3));

    }

}

main is a static method,. And you can access only static members inside a static method. — smk, Feb 22 '13 at 02:55
possible duplicate of [Why main method is static in java](http://stackoverflow.com/questions/3181207/why-main-method-is-static-in-java) — , Feb 22 '13 at 02:57
http://stackoverflow.com/questions/11522026/public-static-void-main-access-non-static-variable — , Feb 22 '13 at 02:59

tckmn · Accepted Answer · 2013-06-29T16:46:23.680

9

main is static. test is not.

If you don't want to make test static, you have to create an instance of SubstringTest first.

SubstringTest st = new SubstringTest(); // create an instance
st.test = "test"; // this works
System.out.println(st.test); // also works

If test is static, you can do

SubstringTest.test = "test";

Or if the code you're writing is in the class SubstringTest and test is static:

test = "test";

edited Jun 29 '13 at 16:46

answered Feb 22 '13 at 02:55

tckmn

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instance of SubstringTest? – Evorlor Feb 22 '13 at 02:57
gotcha thanks doorknob! thats the part i understood about static which is why i was confused. now it makes sense! – Evorlor Feb 22 '13 at 03:00
i am in the class and did test = "test" but thats where the static error came from – Evorlor Feb 22 '13 at 03:09

Achintya Jha · Answer 2 · 2013-02-22T03:02:22.407

A static method cannot access non-static/instance variables, because a static method is never associated with any instance. A static method can’t directly invoke a non-static variable. But static method can access non-static variable by means of declaring instances and using them.

public class SubstringTest
{
private String test; // make it private static String test;

public static void main(String[] args)
{   // SubstringTest t = new SubstringTest(); Or change here.
    // t.test ="Penguin";
    test = "Penguin";
    System.out.println(test);
    System.out.println(test.substring(3));

}

}

score 4 · Answer 3 · answered Feb 22 '13 at 02:56

You CANNOT access instance variables from a Static method.

Because a static method is called on a class instance and not to an object of a class. This means, that a static method is not able to access instance variables, because they are only instantiated in an object

Static Variable Unwanted

3 Answers3