Create following class:

package org.test.netbeans;

public class MainClass {

    private final String one;
    private final String two;

    public MainClass(String one, String two) {
        this.one = one;
        this.two = two;
    }

    protected String getOne() {
        return one;
    }

    protected String getTwo() {
        return two;
    }

}


Invoke "Extract superclass" dialog, mark "one" and "getOne()" for extraction and press "Refactor" button.

Superclass will have only no-args constructor and will leave final field "one" uninitialized. MainClass constructor will not be changed at all, showing error on assignment line.