OnJava8-Examples/generics/GenericHolder.java

// generics/GenericHolder.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.

public class GenericHolder<T> {
  private T a;
  public GenericHolder() {}
  public void set(T a) { this.a = a; }
  public T get() { return a; }
  public static void main(String[] args) {
    GenericHolder<Automobile> h3 =
      new GenericHolder<Automobile>();
    h3.set(new Automobile()); // type checked
    Automobile a = h3.get(); // No cast needed
    //- h3.set("Not an Automobile"); // Error
    //- h3.set(1); // Error
  }
}