8165550: Add class loader names to ClassCastException message

Adds new format of class loader names to VM ClassCastException messages

Reviewed-by: dholmes, mchung, lfoltan

hotspot/src/share/vm/classfile/moduleEntry.cpp

@@ -54,6 +54,17 @@ void ModuleEntry::set_location(Symbol* location) {
   }
 }
 
+bool ModuleEntry::is_non_jdk_module() {
+  ResourceMark rm;
+  if (location() != NULL) {
+    const char* loc = location()->as_C_string();
+    if (strncmp(loc, "jrt:/java.", 10) != 0 && strncmp(loc, "jrt:/jdk.", 9) != 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
 void ModuleEntry::set_version(Symbol* version) {
   if (_version != NULL) {
     // _version symbol's refcounts are managed by ModuleEntry,

hotspot/src/share/vm/classfile/moduleEntry.hpp

@@ -36,6 +36,7 @@
 #include "utilities/ostream.hpp"
 
 #define UNNAMED_MODULE "Unnamed Module"
+#define JAVA_BASE_NAME "java.base"
 
 class ModuleClosure;
 
@@ -100,6 +101,7 @@ public:
 
   Symbol*          location() const                    { return _location; }
   void             set_location(Symbol* location);
+  bool             is_non_jdk_module();
 
   bool             can_read(ModuleEntry* m) const;
   bool             has_reads() const;

hotspot/src/share/vm/classfile/systemDictionary.cpp

@@ -2897,11 +2897,11 @@ void SystemDictionary::verify() {
 // caller needs ResourceMark
 const char* SystemDictionary::loader_name(const oop loader) {
   return ((loader) == NULL ? "<bootloader>" :
-    InstanceKlass::cast((loader)->klass())->name()->as_C_string());
+          InstanceKlass::cast((loader)->klass())->name()->as_C_string());
 }
 
 // caller needs ResourceMark
 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
   return (loader_data->class_loader() == NULL ? "<bootloader>" :
-    InstanceKlass::cast((loader_data->class_loader())->klass())->name()->as_C_string());
+          SystemDictionary::loader_name(loader_data->class_loader()));
 }

hotspot/src/share/vm/runtime/sharedRuntime.cpp

@@ -55,6 +55,7 @@
 #include "runtime/handles.inline.hpp"
 #include "runtime/init.hpp"
 #include "runtime/interfaceSupport.hpp"
+#include "runtime/java.hpp"
 #include "runtime/javaCalls.hpp"
 #include "runtime/sharedRuntime.hpp"
 #include "runtime/stubRoutines.hpp"
@@ -1933,44 +1934,103 @@ char* SharedRuntime::generate_class_cast_message(
   return generate_class_cast_message(caster_klass, target_klass);
 }
 
+// The caller of class_loader_and_module_name() (or one of its callers)
+// must use a ResourceMark in order to correctly free the result.
+const char* class_loader_and_module_name(Klass* klass) {
+  const char* delim = "/";
+  size_t delim_len = strlen(delim);
+
+  const char* fqn = klass->external_name();
+  // Length of message to return; always include FQN
+  size_t msglen = strlen(fqn) + 1;
+
+  bool has_cl_name = false;
+  bool has_mod_name = false;
+  bool has_version = false;
+
+  // Use class loader name, if exists and not builtin
+  const char* class_loader_name = "";
+  ClassLoaderData* cld = klass->class_loader_data();
+  assert(cld != NULL, "class_loader_data should not be NULL");
+  if (!cld->is_builtin_class_loader_data()) {
+    // If not builtin, look for name
+    oop loader = klass->class_loader();
+    if (loader != NULL) {
+      oop class_loader_name_oop = java_lang_ClassLoader::name(loader);
+      if (class_loader_name_oop != NULL) {
+        class_loader_name = java_lang_String::as_utf8_string(class_loader_name_oop);
+        if (class_loader_name != NULL && class_loader_name[0] != '\0') {
+          has_cl_name = true;
+          msglen += strlen(class_loader_name) + delim_len;
+        }
+      }
+    }
+  }
+
+  const char* module_name = "";
+  const char* version = "";
+  Klass* bottom_klass = klass->is_objArray_klass() ?
+    ObjArrayKlass::cast(klass)->bottom_klass() : klass;
+  if (bottom_klass->is_instance_klass()) {
+    ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
+    // Use module name, if exists
+    if (module->is_named()) {
+      has_mod_name = true;
+      module_name = module->name()->as_C_string();
+      msglen += strlen(module_name);
+      // Use version if exists and is not a jdk module
+      if (module->is_non_jdk_module() && module->version() != NULL) {
+        has_version = true;
+        version = module->version()->as_C_string();
+        msglen += strlen("@") + strlen(version);
+      }
+    }
+  } else {
+    // klass is an array of primitives, so its module is java.base
+    module_name = JAVA_BASE_NAME;
+  }
+
+  if (has_cl_name || has_mod_name) {
+    msglen += delim_len;
+  }
+
+  char* message = NEW_RESOURCE_ARRAY_RETURN_NULL(char, msglen);
+
+  // Just return the FQN if error in allocating string
+  if (message == NULL) {
+    return fqn;
+  }
+
+  jio_snprintf(message, msglen, "%s%s%s%s%s%s%s",
+               class_loader_name,
+               (has_cl_name) ? delim : "",
+               (has_mod_name) ? module_name : "",
+               (has_version) ? "@" : "",
+               (has_version) ? version : "",
+               (has_cl_name || has_mod_name) ? delim : "",
+               fqn);
+  return message;
+}
+
 char* SharedRuntime::generate_class_cast_message(
     Klass* caster_klass, Klass* target_klass) {
 
-  const char* caster_klass_name = caster_klass->external_name();
-  Klass* c_klass = caster_klass->is_objArray_klass() ?
-    ObjArrayKlass::cast(caster_klass)->bottom_klass() : caster_klass;
-  ModuleEntry* caster_module;
-  const char* caster_module_name;
-  if (c_klass->is_instance_klass()) {
-    caster_module = InstanceKlass::cast(c_klass)->module();
-    caster_module_name = caster_module->is_named() ?
-      caster_module->name()->as_C_string() : UNNAMED_MODULE;
-  } else {
-    caster_module_name = "java.base";
-  }
-  const char* target_klass_name = target_klass->external_name();
-  Klass* t_klass = target_klass->is_objArray_klass() ?
-    ObjArrayKlass::cast(target_klass)->bottom_klass() : target_klass;
-  ModuleEntry* target_module;
-  const char* target_module_name;
-  if (t_klass->is_instance_klass()) {
-    target_module = InstanceKlass::cast(t_klass)->module();
-    target_module_name = target_module->is_named() ?
-      target_module->name()->as_C_string(): UNNAMED_MODULE;
-  } else {
-    target_module_name = "java.base";
-  }
+  const char* caster_name = class_loader_and_module_name(caster_klass);
 
-  size_t msglen = strlen(caster_klass_name) + strlen(caster_module_name) +
-     strlen(target_klass_name) + strlen(target_module_name) + 50;
+  const char* target_name = class_loader_and_module_name(target_klass);
 
-  char* message = NEW_RESOURCE_ARRAY(char, msglen);
-  if (NULL == message) {
+  size_t msglen = strlen(caster_name) + strlen(" cannot be cast to ") + strlen(target_name) + 1;
+
+  char* message = NEW_RESOURCE_ARRAY_RETURN_NULL(char, msglen);
+  if (message == NULL) {
     // Shouldn't happen, but don't cause even more problems if it does
-    message = const_cast<char*>(caster_klass_name);
+    message = const_cast<char*>(caster_klass->external_name());
   } else {
-    jio_snprintf(message, msglen, "%s (in module: %s) cannot be cast to %s (in module: %s)",
-      caster_klass_name, caster_module_name, target_klass_name, target_module_name);
+    jio_snprintf(message,
+                 msglen,
+                 "%s cannot be cast to %s",
+                 caster_name,
+                 target_name);
   }
   return message;
 }

hotspot/test/runtime/modules/CCE_module_msg.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 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
@@ -23,17 +23,39 @@
 
 /**
  * @test
- * @run main/othervm CCE_module_msg
+ * @modules java.base/jdk.internal.misc
+ * @library /test/lib ..
+ * @compile p2/c2.java
+ * @compile p4/c4.java
+ * @build sun.hotspot.WhiteBox
+ * @compile/module=java.base java/lang/reflect/ModuleHelper.java
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ *                              sun.hotspot.WhiteBox$WhiteBoxPermission
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI CCE_module_msg
  */
 
+import java.io.*;
+import java.lang.reflect.Module;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import static jdk.test.lib.Asserts.*;
+
 // Test that the message in a runtime ClassCastException contains module info.
 public class CCE_module_msg {
+    private static final Path CLASSES_DIR = Paths.get("classes");
 
-    public static void main(String[] args) {
-        invalidCastTest();
+    public static void main(String[] args) throws Throwable {
+        // Should not display version
+        invalidObjectToDerived();
+        // Should display version
+        invalidClassToString();
+        // Should display customer class loader
+        invalidClassToStringCustomLoader();
     }
 
-    public static void invalidCastTest() {
+    public static void invalidObjectToDerived() {
         java.lang.Object instance = new java.lang.Object();
         int left = 23;
         int right = 42;
@@ -44,11 +66,69 @@ public class CCE_module_msg {
             throw new RuntimeException("ClassCastException wasn't thrown, test failed.");
         } catch (ClassCastException cce) {
             System.out.println(cce.getMessage());
-            if (!cce.getMessage().contains("java.lang.Object (in module: java.base) cannot be cast")) {
+            if (!cce.getMessage().contains("java.base/java.lang.Object cannot be cast to Derived")) {
                 throw new RuntimeException("Wrong message: " + cce.getMessage());
             }
         }
     }
+
+    public static void invalidClassToString() throws Throwable {
+        // Get the java.lang.reflect.Module object for module java.base.
+        Class jlObject = Class.forName("java.lang.Object");
+        Object jlObject_jlrM = jlObject.getModule();
+        assertNotNull(jlObject_jlrM, "jlrModule object of java.lang.Object should not be null");
+
+        // Get the class loader for CCE_module_msg and assume it's also used to
+        // load classes p1.c1 and p2.c2.
+        ClassLoader this_cldr = CCE_module_msg.class.getClassLoader();
+
+        // Define a module for p2.
+        Object m2 = ModuleHelper.ModuleObject("module2", this_cldr, new String[] { "p2" });
+        assertNotNull(m2, "Module should not be null");
+        ModuleHelper.DefineModule(m2, "9.0", "m2/there", new String[] { "p2" });
+        ModuleHelper.AddReadsModule(m2, jlObject_jlrM);
+
+        try {
+            ModuleHelper.AddModuleExportsToAll(m2, "p2");
+            Object p2Obj = new p2.c2();
+            System.out.println((String)p2Obj);
+            throw new RuntimeException("ClassCastException wasn't thrown, test failed.");
+        } catch (ClassCastException cce) {
+            String exception = cce.getMessage();
+            System.out.println(exception);
+            if (exception.contains("module2/p2.c2") ||
+                !(exception.contains("module2@") &&
+                  exception.contains("/p2.c2 cannot be cast to java.base/java.lang.String"))) {
+                throw new RuntimeException("Wrong message: " + exception);
+            }
+        }
+    }
+
+    public static void invalidClassToStringCustomLoader() throws Throwable {
+        // Get the java.lang.reflect.Module object for module java.base.
+        Class jlObject = Class.forName("java.lang.Object");
+        Object jlObject_jlrM = jlObject.getModule();
+        assertNotNull(jlObject_jlrM, "jlrModule object of java.lang.Object should not be null");
+
+        // Create a customer class loader to load class p4/c4.
+        URL[] urls = new URL[] { CLASSES_DIR.toUri().toURL() };
+        ClassLoader parent = ClassLoader.getSystemClassLoader();
+        MyURLClassLoader myCldr = new MyURLClassLoader("MyClassLoader", urls, parent);
+
+        try {
+            // Class p4.c4 should be defined to the unnamed module of myCldr
+            Class p4_c4_class = myCldr.loadClass("p4.c4");
+            Object c4Obj = p4_c4_class.newInstance();
+            System.out.println((String)c4Obj);
+            throw new RuntimeException("ClassCastException wasn't thrown, test failed.");
+        } catch (ClassCastException cce) {
+            String exception = cce.getMessage();
+            System.out.println(exception);
+            if (!exception.contains("MyClassLoader//p4.c4 cannot be cast to java.base/java.lang.String")) {
+                throw new RuntimeException("Wrong message: " + exception);
+            }
+        }
+    }
 }
 
 class Derived extends java.lang.Object {
@@ -56,3 +136,35 @@ class Derived extends java.lang.Object {
         return right;
     }
 }
+
+class MyURLClassLoader extends URLClassLoader {
+    public MyURLClassLoader(String name,
+                          URL[] urls,
+                          ClassLoader parent) {
+        super(name, urls, parent);
+    }
+
+    public Class loadClass(String name) throws ClassNotFoundException {
+        if (!name.equals("p4.c4")) {
+            return super.loadClass(name);
+        }
+        byte[] data = getClassData(name);
+        return defineClass(name, data, 0, data.length);
+    }
+
+    byte[] getClassData(String name) {
+        try {
+           String TempName = name.replaceAll("\\.", "/");
+           String currentDir = System.getProperty("test.classes");
+           String filename = currentDir + File.separator + TempName + ".class";
+           FileInputStream fis = new FileInputStream(filename);
+           byte[] b = new byte[5000];
+           int cnt = fis.read(b, 0, 5000);
+           byte[] c = new byte[cnt];
+           for (int i=0; i<cnt; i++) c[i] = b[i];
+              return c;
+        } catch (IOException e) {
+           return null;
+        }
+    }
+}

hotspot/test/runtime/modules/p4/c4.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2016, 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * 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).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+// Small class used by multiple hotspot/runtime/modules/AccessCheck* tests.
+package p4;
+
+public class c4 {
+    public void method4() { }
+}