test/hotspot/jtreg/runtime/LoaderConstraints/vtableLdrConstraint/Test.java

rev 49800 : 8199852: Print more information about class loaders in LinkageErrors.
Reviewed-by: dholmes

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2018, 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.

@@ -21,11 +21,11 @@
  * questions.
  */
 
 /*
  * @test
- * @bug 8186092
+ * @bug 8186092 8199852
  * @compile ../common/Foo.java
  *          ../common/J.java
  *          I.java
  *          ../common/C.jasm
  *          Task.java

@@ -33,31 +33,57 @@
  * @run main/othervm Test
  */
 
 public class Test {
 
+    static String expectedErrorMessage1 =
+        "loader constraint violation for class test.Task: " +
+        "when selecting overriding method test.Task.m()Ltest/Foo; " +
+        "the class loader \"<unnamed>\" (instance of PreemptingClassLoader, " +
+        "child of \"app\" jdk.internal.loader.ClassLoaders$AppClassLoader) " +
+        "of the selected method's type test.Task, " +
+        "and the class loader \"app\" (instance of jdk.internal.loader.ClassLoaders$AppClassLoader) " +
+        "for its super type test.J " +
+        "have different Class objects for the type test.Foo used in the signature";
+
+    static String expectedErrorMessage2 =
+        "loader constraint violation for class test.Task: " +
+        "when selecting overriding method test.Task.m()Ltest/Foo; " +
+        "the class loader \"VtableLdrCnstrnt_Test_Loader\" (instance of PreemptingClassLoader, " +
+        "child of \"app\" jdk.internal.loader.ClassLoaders$AppClassLoader) " +
+        "of the selected method's type test.Task, " +
+        "and the class loader \"app\" (instance of jdk.internal.loader.ClassLoaders$AppClassLoader) " +
+        "for its super type test.J " +
+        "have different Class objects for the type test.Foo used in the signature";
+
     // Test that the error message is correct when a loader constraint error is
     // detected during vtable creation.
     //
     // In this test, during vtable creation for class Task, method "Task.m()LFoo;"
     // overrides "J.m()LFoo;".  But, Task's class Foo and super type J's class Foo
     // are different.  So, a LinkageError exception should be thrown because the
     // loader constraint check will fail.
-    public static void main(String args[]) throws Exception {
-        Class<?> c = Foo.class; // forces standard class loader to load Foo
-        ClassLoader l = new PreemptingClassLoader("Task", "Foo", "I");
-        l.loadClass("Foo");
+    public static void test(String loaderName, String expectedErrorMessage) throws Exception {
+        Class<?> c = test.Foo.class; // Forces standard class loader to load Foo.
+        String[] classNames = {"test.Task", "test.Foo", "test.I"};
+        ClassLoader l = new PreemptingClassLoader(loaderName, classNames);
+        l.loadClass("test.Foo");
         try {
-            l.loadClass("Task").newInstance();
+            l.loadClass("test.Task").newInstance();
             throw new RuntimeException("Expected LinkageError exception not thrown");
         } catch (LinkageError e) {
-            if (!e.getMessage().contains(
-                    "loader constraint violation for class Task: when selecting overriding method") ||
-                !e.getMessage().contains(
-                    "for its super type J have different Class objects for the type Foo")) {
-                throw new RuntimeException("Wrong LinkageError exception thrown: " + e.getMessage());
+            String errorMsg = e.getMessage();
+            if (!errorMsg.equals(expectedErrorMessage)) {
+                System.out.println("Expected: " + expectedErrorMessage + "\n" +
+                                   "but got:  " + errorMsg);
+                throw new RuntimeException("Wrong LinkageError exception thrown: " + errorMsg);
             }
+            System.out.println("Passed with message: " + errorMsg);
         }
     }
 
+    public static void main(String args[]) throws Exception {
+        test(null, expectedErrorMessage1);
+        test("VtableLdrCnstrnt_Test_Loader", expectedErrorMessage2);
+    }
 }