Java example source code file (WarnUnderscoreAsIdent.java)

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Java - Java tags/keywords

string, throwable

The WarnUnderscoreAsIdent.java Java example source code

/*
 * Copyright (c) 2013, 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @summary Check usages of underscore as identifier generate warnings
 * @compile/fail/ref=WarnUnderscoreAsIdent.out -XDrawDiagnostics -Werror WarnUnderscoreAsIdent.java
 */
package _._;

import _._;

class _ {
    String _ = null;
    void _(String _) { }
    void testLocal() {
        String _ = null;
    }
    void testFor() {
        for (int _ = 0; _ < 10; _++);
    }
    void testTry() {
        try { } catch (Throwable _) { }
    }
    void testLabel() {
        _:
        for (;;) {
            break _;
        }
        _:
        for (;;) {
            continue _;
        }
    }
}