Non-static variable of cannot be referenced from a static context [duplicate]

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Non-static variable cannot be referenced from a static context (15 answers)

Closed 8 years ago.

I'm trying to call my createFile method from the OpenFile class in my main method, but I keep getting the error saying that I cannot call a non-static variable from a static context.

I did try calling OpenFile of = new OpenFile(); inside my main method, but that didn't work so I'm currently declaring OpenFile above my main method which works fine, however every time I try to use one of OpenFiles methods I get the same error.

I've tried prefacing a few things with static but that just causes my IDE to show an Erroneous sym type error, which I think is caused by whatever is causing the other error.

Here is createFile from OpenFile:

public class OpenFile {

    private Formatter file;

    public void createFile() throws FileNotFoundException{

        try{
            file = new Formatter("test.txt");
        } catch(Exception e) {
            System.out.println("Error creating file.");
    }
    }

and here is my main method:

OpenFile of = new OpenFile();

public static void main(String[] args) {
    // TODO code application logic here

    of.createFile();
    intro();
    createAndShowRibbon();
    createAndShowNormalUI();

}

Is it something to do with Formatter? I've never used it before.

Thanks.

Answer 1

OpenFile of = new OpenFile();

should be

static OpenFile of = new OpenFile();

You're accessing it from your static void main method. If this variable is not declared static, it will not be available to the method when it is statically executed.

Answer 2

Since main method in java is most popular method among all beginners and they try to put program code there they face "non-static variable cannot be referenced from a static context" compiler error when they try to access a non static member variable inside main in Java which is static.

Please take a look at this article
Why non-static variable cannot be referenced from a static context?

---

In your case you have to make the OpenFile of = new OpenFile(); instantiation to be static like as shown below in order to access that in main method which is a static method.

static OpenFile of = new OpenFile();  // should be static for accessing within main method
public static void main(String[] args) {

    of.createFile();
    intro();
    createAndShowRibbon();
    createAndShowNormalUI();

}

Answer 3

The following is non-static.

OpenFile of = new OpenFile();

But you're calling it from a main method, which is static.

Try changing to:

static OpenFile of = new OpenFile();

Answer 4

in the static method u can call Class methods or variables which is static but u can't call instance variables or method in