test/hotspot/jtreg/runtime/HiddenClasses/CastToParentTest.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 *
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 * 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,
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/*
 * @test
 * @summary Test that a hidden class can be cast to its parent.
 * DESCRIPTION
 *     Try to cast an object of a hidden class to its parent (called CastToParentTest)
 *         - (CastToParentTest) o
 *         - o.getClass().cast(<hiddenClassObj>);
 *     and cast to its grandparent (java.lang.Object).
 *
 * @library /test/lib
 * @modules jdk.compiler
 * @run main CastToParentTest
 */

import java.lang.invoke.MethodType;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import static java.lang.invoke.MethodHandles.Lookup.ClassOption.*;
import jdk.test.lib.compiler.InMemoryJavaCompiler;

public class CastToParentTest {

    static byte klassbuf[] = InMemoryJavaCompiler.compile("TestClass",
        "public class TestClass extends CastToParentTest { " +
        "    public static void concat(String one, String two) throws Throwable { " +
        "        System.out.println(one + two);" +
        " } } ");

    public static void main(String[] args) throws Throwable {
        Lookup lookup = MethodHandles.lookup();
        Class<?> c = lookup.defineHiddenClass(klassbuf, false, NESTMATE).lookupClass();
        Object hiddenClassObj = c.newInstance();

        // Cast hidden class to its parent.
        CastToParentTest parentObj = (CastToParentTest)hiddenClassObj;

        if (!parentObj.equals(hiddenClassObj)) {
            throw new RuntimeException("Hidden class object cannot be cast to parent");
        }

        // Try to cast using a different mechanism.
        new CastToParentTest().getClass().cast(hiddenClassObj);


        // Cast hidden class to its grandparent.
        java.lang.Object grandparentObj = (java.lang.Object)hiddenClassObj;

        if (!grandparentObj.equals(hiddenClassObj)) {
            throw new RuntimeException("Hidden class object cannot be cast to grandparent");
        }

        // Try to cast using a different mechanism.
        new java.lang.Object().getClass().cast(hiddenClassObj);
    }

}