package generics;

import java.util.*;

/**

* RUN:

* javac generics/ErasureAndInheritance.java && javac generics.ErasureAndInheritance

* OUTPUT:

*

*/

public class ErasureAndInheritance {

@SuppressWarnings("unchecked")

public static void main(String[] args) {

Derived2 d2 = new Derived2();

Object obj = d2.get();

d2.set(obj); // Note: generics\ErasureAndInheritance.java uses unchecked or unsafe operations.

// Note: Recompile with -Xlint:unchecked for details.

}

}

class GenericBase<T> {

private T element;

public void set(T arg) { element =arg; }

public T get() { return element; }

}

class Derived1<T> extends GenericBase<T> {}

class Derived2 extends GenericBase {}

/*

*

* error: unexpected type

* class Derived3 extends GenericBase<?> {}

* ^

* required: class or interface without bounds

* found: ?

* 1 error

*

*/

class Derived3 extends GenericBase<?> {}