Generics Default Constructor Java

Question

public class Sample<T>{

 T data;

   Sample(){

     data = ????;

  }

}

How can i assign a default value to data ?

johncip · Accepted Answer · 2010-10-18 08:33:40Z

8

Bozho is right (you can't). If you definitely want it to start off with a value, make that value an argument to the constructor. For instance:

public class Sample<T> {
  T data;
  Sample(T data) {
     this.data = data;
  }
}

answered Oct 18, 2010 at 7:33

johncip

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Comments

Bozho · Accepted Answer · 2010-10-18 07:29:59Z

7

You can't. The type T is erased at runtime, so you can't instantiate it.

If you pass a Class argument to the Sample(..) constructor, you can call clazz.newInstance()

answered Oct 18, 2010 at 7:29

Bozho

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"You can't." ... unless the default value is null. :-)