ClassLiteralWastesByteTest.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
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 *
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 * 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).
 *
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 * 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 4965689
 * @summary class literal code wastes a byte
 * @modules jdk.compiler
 *          jdk.jdeps/com.sun.tools.javap
 */

import java.io.PrintWriter;
import java.io.StringWriter;
import java.nio.file.Paths;

public class ClassLiteralWastesByteTest {

    private static final String assertionErrorMsg =
            "Instead of ldc_w, ldc instruction should have been generated";

    public static void main(String[] args) {
        new ClassLiteralWastesByteTest().run();
    }

    void run() {
        check("-c", Paths.get(System.getProperty("test.classes"),
                "test.class").toString());
    }

    void check(String... params) {
        StringWriter s;
        String out;
        try (PrintWriter pw = new PrintWriter(s = new StringWriter())) {
            com.sun.tools.javap.Main.run(params, pw);
            out = s.toString();
        }
        if (out.contains("ldc_w")) {
            throw new AssertionError(assertionErrorMsg);
        }
    }

}

class test {
    void m() {
        Class<?> aClass = test.class;
    }
}