Cannot make a static reference to the non-static method setString(String) from the type MyString

Question

I need to create a class for the methods described in the interface as follows:

public interface MyStringInterface {

    // Sets the value of the current string
    public void setString(String str);

    // Returns the current string
    public String getString();
}

When I create a class with methods as below, there is always this error and wont let me proceed. What am I doing wrong? How should I proceed?

package seclass.assgn;

public class MyString implements MyStringInterface{

    static String name;

    public static void main(String[] args) {            
        setString("This is my sentence");
        System.out.println(getString());
    }

    public void setString(String str){
        name = str;
    }
    public String getString() {
        return name;
    }
}

You should consult the thousands of other such questions, some of which you can find on your right, under the _Related_ section. — Sotirios Delimanolis, Sep 02 '14 at 04:32
`setString()` and `getString()` are non-static methods, so they cannot be referenced from a static context. — August, Sep 02 '14 at 04:33
One way to make this work is simply making your `name` non-static by removing the `static` modifier. — lxcky, Sep 02 '14 at 04:37

score 1 · Answer 1 · answered Sep 02 '14 at 04:36

You need an instance of MyString -

public static void main(String[] args) {
  MyString my = new MyString();            
  my.setString("This is my sentence");
  System.out.println(my.getString());
}

also

static String name;

should be

private String name;

Alternatively, if you don't want an instance just use

public static void main(String[] args) {
  name = "This is my sentence";
  System.out.println(name);
}

score 1 · Answer 2 · edited Sep 02 '14 at 04:56

1

First of all, you don't have to repeat "public" in interfaces.

public interface MyStringInterface {
    void   setString(String str);
    String getString();
} // end of class MyStringInterface

Then you must make an Object of your implementation:

public class MyString implements MyStringInterface {
String name;

public static void main(String[] args) {
    new MyString().top();
}


void top() {
    setString("This is my sentence.");
    System.out.println(getString());
}


@Override
public void setString(String str) {
    this.name = str;
}


@Override
public String getString() {
    return this.name;
}

} // end of class MyString

edited Sep 02 '14 at 04:56

takendarkk

3,347
8
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answered Sep 02 '14 at 04:55

iGeeks

192
1
11

Good! +1 for correct answer and for mentioning to not use the `public` keyword for interface members. – Seelenvirtuose Sep 02 '14 at 06:00
Even better would be, to separate the test-program from the implementation. But I think, that was not the question. – iGeeks Sep 02 '14 at 08:03

Cannot make a static reference to the non-static method setString(String) from the type MyString

2 Answers2