"Error: non-static variable this cannot be referenced from a static context" in calculation class

Question

My instance of the class "Conversion" returns this error when I compile the program.

import java.util.Scanner;

public class Convert {

    private class Conversion{

        public String getConversion(int inchInput) {
            int yards = (inchInput - (inchInput % 36)) / 36;
            int feet =  (inchInput % 36) - ((inchInput % 36) % 12);
            int inches = (inchInput % 36) % 12;

            return yards + "yards, " + feet + "feet, and " + inches + "inches.";
        }

    } // end of class Conversion

    public static void main( String[] args ) {
        Scanner scanner = new Scanner(System.in);
        int inchInput;
        Conversion conversion;
        conversion = new Conversion();

        // prompt
        System.out.println("Please enter an amout of inches (integer): ");
        inchInput = scanner.nextInt();
        String output = conversion.getConversion(inchInput);
    } // end of method main()
} // enf of class Convert

On what line is the exception occuring? – Richard Tingle Sep 09 '13 at 13:36 — Richard Tingle, Sep 09 '13 at 13:36

Prabhaker A · Answer 1 · 2013-09-09T13:40:49.710

Conversion is inner class to Convert.So you can't access it directly.
You need to create Conversion object like this.

Convert convert =new Convert();
Conversion conversion;
conversion = convert.new Conversion();

or declare the Conversion as static

 class Convert {
   private static class Conversion{
     ...............
      ............
  }
}

and create Conversion object like this

Conversion conversion = new Convert.Conversion();

score 2 · Answer 2 · answered Sep 09 '13 at 13:35

2

Make the Conversion class static so that there is an accesible enclosed instance of the class

private static class Conversion {
  ...
}

answered Sep 09 '13 at 13:35

Reimeus

158,255
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...or move it outside, as general-purpose classes would be. – nanofarad Sep 09 '13 at 13:36
There's some more helpful explanation here: http://stackoverflow.com/questions/70324/java-inner-class-and-static-nested-class – Dave Costa Sep 09 '13 at 13:39

score 1 · Answer 3 · answered Sep 09 '13 at 13:44

1

set modifier of class to static

private static class Conversion

at

answered Sep 09 '13 at 13:44

Sumit Lubal

329
2
13

score 0 · Answer 4 · answered Sep 09 '13 at 13:39

0

You need probably:

Convert.Conversion cc = new Convert().new Conversion();
cc.getConversion(...);
...

answered Sep 09 '13 at 13:39

arjacsoh

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"Error: non-static variable this cannot be referenced from a static context" in calculation class

4 Answers4