SuperfluousAbstract.java

/*
 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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 */

/*
 * @test
 * @bug 4912795
 * @summary AbstractMethodError throws if not redeclare abstract iterator() method
 * @author gafter
 */

import java.util.AbstractCollection;
import java.util.Collection;
import java.util.Iterator;

interface Q<E> extends Collection<E> {}

abstract class AbstractQ<E> extends AbstractCollection<E> implements Q<E> {
    // Uncomment this to avoid the AbstractMethodError:
    //public abstract Iterator<E> iterator();
}

class ConcreteQ<E> extends AbstractQ<E> {
    public int size() { return 0; }
    public Iterator<E> iterator() { return null; }
}

public class SuperfluousAbstract {
    public static void main(String[] args) {
        try {
            Q<Integer> q = new ConcreteQ<Integer>() ;
            for (Integer i : q) {}
        }
        catch (AbstractMethodError e) {
            e.printStackTrace(System.err);
        }
        catch (NullPointerException e) {
            // expected, since iterator() returns null
        }
    }
}