Generic Constructors

It is possible for constructors to be generic, even if their class is not. For example, consider the following short program:

 
class MyClass {
  private double val;

  <T extends Number> MyClass(T arg) {
    val = arg.doubleValue();
  }

  void showval() {
    System.out.println("val: " + val);
  }
}

public class Main {
  public static void main(String args[]) {
    MyClass test = new MyClass(100);
    MyClass test2 = new MyClass(123.5F);
    test.showval();
    test2.showval();
  }
}

Home
Java Book
Language Basics

Generics: