LdrCnstrFldMsgTest.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * 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
 * @compile pkg/Grand.java pkg/Parent.java pkg/ClassLoaderForParentFoo.java
 * @compile pkg/ClassLoaderForChildGrandFoo.java pkg/Child.jasm
 * @run main/othervm LdrCnstrFldMsgTest
 */

import java.lang.reflect.Method;

// Check that the LinkageError loader constraint message for fields contains the
// correct information.
//
// The test creates two class loaders.  The first class loader loads classes
// Child, Foo, and Grand.  The second class loader loads Parent and Foo.  Class
// Parent is a sub-class of Grand and class Child is a sub-class of Parent.
// Class Child tries to load Parent._field1.  This should fail because type Foo
// for Parent._field1 is a different type than Child's Foo.
//
// Grand (ldr1)   has field _field1 of type Foo(ldr1)
//  |
// Parent (ldr2)  has field _field1 of type Foo(ldr2)
//  |
// Child (ldr1)
//
// java.lang.LinkageError: loader constraint violation:
//   when resolving field "_field1" of type pkg.Foo,
//   the class loader pkg.ClassLoaderForChildGrandFoo @42b2e259 of the current class, pkg.Child,
//   and the class loader pkg.ClassLoaderForParentFoo @4b55c90f for the field's defining class, pkg.Parent,
//   have different Class objects for type pkg.Foo
//   (pkg.Child is in unnamed module of loader pkg.ClassLoaderForChildGrandFoo @42b2e259, parent loader 'app';
//    pkg.Parent is in unnamed module of loader pkg.ClassLoaderForParentFoo @4b55c90f, parent loader 'app')
//
public class LdrCnstrFldMsgTest {
    public static void main(String... args) throws Exception {
        ClassLoader l = new pkg.ClassLoaderForChildGrandFoo("pkg.Foo", "pkg.Child", "pkg.Grand");
        l.loadClass("pkg.Foo");

        // Try to call a public method in Grand.
        Runnable r = (Runnable) l.loadClass("pkg.Child").newInstance();
        try {
            r.run();
            throw new RuntimeException("Expected LinkageError exception not thrown");
        } catch (java.lang.LinkageError e) {
            if (!e.getMessage().contains("for the field's defining class, pkg.Parent,") ||
                !e.getMessage().contains("have different Class objects for type pkg.Foo")) {
                throw new RuntimeException("Wrong LinkageError exception thrown: " + e.toString());
            }
        }
    }
}