Attachment 90208 Details for Bug 219625 – Java class demonstrating bug

Java class demonstrating bug

GenericsAbstractMethodError.java (text/x-java), 1.22 KB, created by Matt Hillsdon

on 2008-02-20 12:13:23 EST

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Creator: Matt Hillsdon

Created: 2008-02-20 12:13:23 EST

Size: 1.22 KB

patch

obsolete

>
>/**
> * There appears to be a bug in the type checking.
> *
> * @copyright
> * @author mth
> */
>public class GenericsAbstractMethodError {
>
>  interface Foo<T> {
>    T getValue();
>    void doSomething(T o);
>  }
>
>  public static abstract class AbstractFoo<T> implements Foo<T> {
>    /**
>     * If this is removed ConcreteFoo no longer compiles.
>     */
>    public void doSomething(final String o) {
>    }
>  }
>
>  public static final class ConcreteFoo extends AbstractFoo<String> {
>    public String getValue() {
>      return "I am a string";
>    }
>  }
>
>  /**
>   * We lose the type infomation here so try but fail to call the doSomething(Object) method.
>   */
>  private static <T> void feedFoosValueIntoFoo(final Foo<T> foo) {
>    foo.doSomething(foo.getValue());
>  }
>
>  private static void testTypedString() {
>    final ConcreteFoo foo = new ConcreteFoo();
>    foo.doSomething(foo.getValue());
>  }
>
>  /**
>   * This gives an AbstractMethodError in Eclipse 3.3.1.1
>   * but (interestingly) works fine in Sun Java 1.6.0_03.
>   */
>  private static void testGenericString() {
>    feedFoosValueIntoFoo(new ConcreteFoo());
>  }
>
>  public static void main(String[] args) {
>    testTypedString();
>    testGenericString();
>    System.out.println("Success.");
>  }
>
>}
>

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