Is it must to call super class constructor?

[Ramana Uppala]

This program gives me compile time error.Is it must to call super class constructor?

class Sup{
public Sup(String str){
System.out.println("Super class");
}
}

public class Class1 extends Sup{
public Class1(){
System.out.println("sub class");
}
public static void main(String[] args) {
Class1 t2 = new Class1();
}
}

[Jeroen Wenting]

If you extend a class which does not have a no-argument constructor you must indeed call the constructor (using super) explicitly in the constructors of your derived classes.

[Subhash Bhushan C]

If you don�t type a constructor into your class code, a default constructor will be automatically generated by the compiler. The default constructor is always a no-arg constructor. If you want a no-arg constructor and you�ve typed any other constructors into your class code, the compiler won�t provide the no-arg constructor for you. In other words, if you�ve typed in a constructor with arguments, you won�t have a no-arg constructor unless you type it in yourself. If you do type in a constructor, and you do not type in the call to super(), the compiler will insert a no-arg call to super() for you.

If your super constructor (that is, the constructor of your immediate superclass/parent) has arguments, you must type in the call to super(), supplying the appropriate arguments. If your superclass does not have a no-arg constructor, you must type a constructor in your class (the subclass) because you need a place to put in the call to super with the appropriate arguments.

Hope this helps..