Accessing instance variables from a subclass in java
<p>This is my superclass</p>

<pre><code>package ruleta;
import wheels.Wheel;

public class Resolving{

private int nummerCases;    
private int[][] forbidenCases;
protected int[] initialConfiguration;
protected int[] targetConfiguration;


public Resolving(){
}

public Resolving(int[][] obj, int nummer){
    this.forbidenCases = obj;
    this.nummerCases = nummer;
}

protected void setiConfiguration(int[] array){
    this.initialConfiguration = array;
}

protected int[] getiConfiguration(){
    return initialConfiguration;
}

protected void settConfiguration(int[] array){
    this.targetConfiguration = array;
}

protected int[] gettConfiguration(){
    return this.targetConfiguration;
}

public void run(){

    setiConfiguration(forbidenCases[0]);
    settConfiguration(forbidenCases[1]);

    for(int i=0;i&lt;4;i++){
        System.out.println(initialConfiguration[i]);
    }

    Wheel roulette = new Wheel();

}   
}
</code></pre>

<p>the question is, why if I access to a instance variable from a superclass (Resolving), it always returns the value null? 
On trying to do that: <code>final int[] iC = super.getiConfiguration();</code> it returns me that:</p>

<pre><code>Exception in thread "main" java.lang.NullPointerException
    at wheels.Wheel.&lt;init&gt;(Wheel.java:32)
    at ruleta.Resolving.run(Resolving.java:60)
    at ruleta.Resolving.&lt;init&gt;(Resolving.java:30)
    at ruleta.Arguments.runningFunction(Arguments.java:111)
    at ruleta.Arguments.&lt;init&gt;(Arguments.java:15)
    at main.Main.main(Main.java:7)
</code></pre>

<p>I don't know if it's because of me, that i haven't understand well the Inheritance Java system. Thank you</p>
