class ClassA {
    public void methodA() {
        ClassB classB = new ClassB();
        classB.getValue();
    }
}

class ClassB {
    public ClassC classC;
    public String getValue() {
        return classC.getValue();
    }
}

class ClassC {
    public String value;
    public String getValue() {
        value = "ClassB";
        return value;
    }
}

public class Question {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ClassA a = new ClassA();
        a.methodA();
    }

}



//Exception in thread "main" java.lang.NullPointerException
//    at ClassB.getValue(Question.java:11)
//    at ClassA.methodA(Question.java:4)
//    at Question.main(Question.java:31)