ERROR - Cannot refer to an instance field url while explicitly invoking a constructor

Error

Cannot refer to an instance field url while explicitly invoking a constructor while calling super constructor with member element as the argument.

Error Type

Compile Time

Cause

Instance fields cannot be refereed while explicitly invoking the constructor.

Sample Code 

1.

String url = "";

public MyClass() {
      super(url);    // gives error "Cannot refer to an instance field url while explicitly invoking a constructor"
}

Possible Resolution 1

Declare the url static

static String url = "";

public MyClass() {
      super(url);    
} 

Possible Resolution 2

Specify instance other than the existing ( this.url won't work )

String url = "";

public MyClass() {
      super(new MyClass().url);    

}