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Base class constructor  RSS feed

 
Tmmet Johnson
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Hi ,
What will happen if I have a derived class default constructor which does not call the base class constructor as below?
Will this cause any issues?
Thanks,

public class Base{
private String st = null;
public Base (){}
public Base(String str){
st = str;
}}

public class Derived extends Base{
public Derived(){}

}
}
 
Petrus Pelser
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No. The first line in a constructor must either be a call to super() which calls the superclass' constructor, or a call to this() which calls an overloaded constructor. If there are no call to this() or super(), the compiler will insert an implicit call to super() as the first line of your constructor. In your case, if you create an instance of the derived class, the default constructor of your base class will be called.
 
Petrus Pelser
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Another thing: In this case, if your base class did not have a no-args constructor, you will recieve a compiler error as the implicit call to super() with no arguments would be invalid.
 
sven studde
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cross posted
 
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