1 /*
 2  * Copyright (c) 2025, 2026, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 
24 /*
25  * @test
26  * @summary Test that IsIdentityClass and modifiers return true for arrays that can be flattened.
27  * @library /test/lib
28  * @enablePreview false
29  * @modules java.base/jdk.internal.misc
30  *          java.base/jdk.internal.value
31  * @run junit/othervm IsIdentityClassTest
32  * @run junit/othervm --enable-preview IsIdentityClassTest
33  */
34 
35 import org.junit.jupiter.api.Test;
36 
37 import java.lang.classfile.ClassFile;
38 import java.lang.reflect.AccessFlag;
39 import java.lang.reflect.Modifier;
40 import java.util.Set;
41 
42 import jdk.internal.misc.PreviewFeatures;
43 
44 import static jdk.test.lib.Asserts.*;
45 
46 public class IsIdentityClassTest {
47 
48     @Test
49     void testIsIdentityClass() {
50         assertEquals(!PreviewFeatures.isEnabled(), Integer.class.isIdentity(), "Integer is not an IDENTITY type");
51         assertTrue(Integer[].class.isIdentity(), "Arrays of inline types are IDENTITY types");
52     }
53 
54     @Test
55     void testModifiers() {
56         // Without --enable-preview (before Valhalla), there was no IDENTITY modifier.
57         // With --enable-preview, Integer still should not have the IDENTITY modifier.
58         // So only verify this in preview mode.
59         if (PreviewFeatures.isEnabled()) {
60             int imod = Integer.class.getModifiers();
61             assertFalse((imod & ClassFile.ACC_IDENTITY) != 0,
62                     "Modifier of Integer " + Integer.toHexString(imod) + " should not have ACC_IDENTITY set");
63         }
64         int amod = Integer[].class.getModifiers();
65         assertEquals(PreviewFeatures.isEnabled(), (amod & ClassFile.ACC_IDENTITY) != 0,
66                 "Modifier of array " + Integer.toHexString(amod) + " should have ACC_IDENTITY set");
67     }
68 
69     @Test
70     void testAccessFlags() {
71         // Without --enable-preview (before Valhalla), there was no IDENTITY accessflag.
72         // With --enable-preview, Integer still should not have the IDENTITY accessflag.
73         // So only verify this in preview mode.
74         if (PreviewFeatures.isEnabled()) {
75             Set<AccessFlag> iacc = Integer.class.accessFlags();
76             assertFalse(iacc.contains(AccessFlag.IDENTITY), "Access flags should not contain IDENTITY");
77         }
78         // AccessFlags for arrays set the IDENTITY accessflag.
79         Set<AccessFlag> aacc = Integer[].class.accessFlags();
80         assertEquals(PreviewFeatures.isEnabled(), aacc.contains(AccessFlag.IDENTITY), "Access flags of array of inline types should contain IDENTITY");
81     }
82 }