--- a/hotspot/make/test/JtregNative.gmk	Wed May 03 18:44:27 2017 -0400
+++ b/hotspot/make/test/JtregNative.gmk	Thu May 04 10:05:29 2017 -0400
@@ -56,6 +56,7 @@
     $(HOTSPOT_TOPDIR)/test/runtime/modules/getModuleJNI \
     $(HOTSPOT_TOPDIR)/test/runtime/SameObject \
     $(HOTSPOT_TOPDIR)/test/runtime/BoolReturn \
+    $(HOTSPOT_TOPDIR)/test/runtime/noClassDefFoundMsg \
     $(HOTSPOT_TOPDIR)/test/compiler/floatingpoint/ \
     $(HOTSPOT_TOPDIR)/test/compiler/calls \
     $(HOTSPOT_TOPDIR)/test/serviceability/jvmti/GetNamedModule \

--- a/hotspot/src/share/vm/oops/instanceKlass.cpp	Wed May 03 18:44:27 2017 -0400
+++ b/hotspot/src/share/vm/oops/instanceKlass.cpp	Thu May 04 10:05:29 2017 -0400
@@ -522,7 +522,11 @@
     // if we are executing Java code. This is not a problem for CDS dumping phase since
     // it doesn't execute any Java code.
     ResourceMark rm(THREAD);
-    THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(), external_name(), false);
+    Exceptions::fthrow(THREAD_AND_LOCATION,
+                       vmSymbols::java_lang_NoClassDefFoundError(),
+                       "Class %s, or one of its supertypes, failed class initialization",
+                       external_name());
+    return false;
   }
   // return if already verified
   if (is_linked()) {

--- a/hotspot/src/share/vm/prims/jni.cpp	Wed May 03 18:44:27 2017 -0400
+++ b/hotspot/src/share/vm/prims/jni.cpp	Thu May 04 10:05:29 2017 -0400
@@ -325,7 +325,12 @@
     if (str_len > Symbol::max_length()) {
       // It's impossible to create this class;  the name cannot fit
       // into the constant pool.
-      THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), name);
+      Exceptions::fthrow(THREAD_AND_LOCATION,
+                         vmSymbols::java_lang_NoClassDefFoundError(),
+                         "Class name exceeds maximum length of %d: %s",
+                         Symbol::max_length(),
+                         name);
+      return 0;
     }
     class_name = SymbolTable::new_symbol(name, CHECK_NULL);
   }
@@ -378,8 +383,16 @@
 
   // Sanity check the name:  it cannot be null or larger than the maximum size
   // name we can fit in the constant pool.
-  if (name == NULL || (int)strlen(name) > Symbol::max_length()) {
-    THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), name);
+  if (name == NULL) {
+    THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), "No class name given");
+  }
+  if ((int)strlen(name) > Symbol::max_length()) {
+    Exceptions::fthrow(THREAD_AND_LOCATION,
+                       vmSymbols::java_lang_NoClassDefFoundError(),
+                       "Class name exceeds maximum length of %d: %s",
+                       Symbol::max_length(),
+                       name);
+    return 0;
   }
 
   //%note jni_3

--- a/hotspot/src/share/vm/prims/jvm.cpp	Wed May 03 18:44:27 2017 -0400
+++ b/hotspot/src/share/vm/prims/jvm.cpp	Thu May 04 10:05:29 2017 -0400
@@ -837,13 +837,22 @@
   return result;
 JVM_END
 
+// Currently only called from the old verifier.
 JVM_ENTRY(jclass, JVM_FindClassFromClass(JNIEnv *env, const char *name,
                                          jboolean init, jclass from))
   JVMWrapper("JVM_FindClassFromClass");
-  if (name == NULL || (int)strlen(name) > Symbol::max_length()) {
+  if (name == NULL) {
+    THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), "No class name given");
+  }
+  if ((int)strlen(name) > Symbol::max_length()) {
     // It's impossible to create this class;  the name cannot fit
     // into the constant pool.
-    THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), name);
+    Exceptions::fthrow(THREAD_AND_LOCATION,
+                       vmSymbols::java_lang_NoClassDefFoundError(),
+                       "Class name exceeds maximum length of %d: %s",
+                       Symbol::max_length(),
+                       name);
+    return 0;
   }
   TempNewSymbol h_name = SymbolTable::new_symbol(name, CHECK_NULL);
   oop from_class_oop = JNIHandles::resolve(from);
@@ -919,7 +928,12 @@
     if (str_len > Symbol::max_length()) {
       // It's impossible to create this class;  the name cannot fit
       // into the constant pool.
-      THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), name);
+      Exceptions::fthrow(THREAD_AND_LOCATION,
+                         vmSymbols::java_lang_NoClassDefFoundError(),
+                         "Class name exceeds maximum length of %d: %s",
+                         Symbol::max_length(),
+                         name);
+      return 0;
     }
     class_name = SymbolTable::new_symbol(name, str_len, CHECK_NULL);
   }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/runtime/noClassDefFoundMsg/NoClassDefFoundMsg.java	Thu May 04 10:05:29 2017 -0400
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+
+/*
+ * @test
+ * @bug 8056900
+ * @summary Verifies message returned with NoClassDefFoundError exception.
+ * @library /test/lib
+ * @modules java.base/jdk.internal.misc
+ *          java.compiler
+ * @run main NoClassDefFoundMsg
+ */
+
+import jdk.test.lib.InMemoryJavaCompiler;
+import jdk.internal.misc.Unsafe;
+
+public class NoClassDefFoundMsg {
+
+    static native void callDefineClass(String className);
+    static native void callFindClass(String className);
+    static {
+        System.loadLibrary("NoClassDefFoundMsg");
+    }
+
+
+    public static void main(String args[]) throws Exception {
+        Unsafe unsafe = Unsafe.getUnsafe();
+
+        byte klassbuf[] = InMemoryJavaCompiler.compile("TestClass", "class TestClass { }");
+
+        // Create a class name of length 65536.
+        StringBuilder tooBigClassName = new StringBuilder("z");
+        for (int x = 0; x < 16; x++) {
+            tooBigClassName = tooBigClassName.append(tooBigClassName);
+        }
+
+        // Test JVM_DefineClass() with long name.
+        try {
+            unsafe.defineClass(tooBigClassName.toString(), klassbuf, 4, klassbuf.length - 4, null, null);
+            throw new RuntimeException("defineClass did not throw expected NoClassDefFoundError");
+        } catch (NoClassDefFoundError e) {
+            if (!e.getMessage().contains("Class name exceeds maximum length of ")) {
+                throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
+            }
+        }
+
+        // Test JNI_DefineClass() with long name.
+        try {
+            callDefineClass(tooBigClassName.toString());
+            throw new RuntimeException("DefineClass did not throw expected NoClassDefFoundError");
+        } catch (NoClassDefFoundError e) {
+            if (!e.getMessage().contains("Class name exceeds maximum length of ")) {
+                throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
+            }
+        }
+
+        // Test JNI_FindClass() with long name.
+        try {
+            callFindClass(tooBigClassName.toString());
+            throw new RuntimeException("DefineClass did not throw expected NoClassDefFoundError");
+        } catch (NoClassDefFoundError e) {
+            if (!e.getMessage().contains("Class name exceeds maximum length of ")) {
+                throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
+            }
+        }
+
+        // Test JNI_FindClass() with null name.
+        try {
+            callFindClass(null);
+            throw new RuntimeException("FindClass did not throw expected NoClassDefFoundError");
+        } catch (NoClassDefFoundError e) {
+            if (!e.getMessage().contains("No class name given")) {
+                throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
+            }
+        }
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/runtime/noClassDefFoundMsg/libNoClassDefFoundMsg.c	Thu May 04 10:05:29 2017 -0400
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+
+#include <jni.h>
+
+JNIEXPORT void JNICALL
+Java_NoClassDefFoundMsg_callDefineClass(JNIEnv *env, jclass klass, jstring className) {
+    const char *c_name = (*env)->GetStringUTFChars(env, className, NULL);
+    (*env)->DefineClass(env, c_name, NULL, NULL, 0);
+}
+
+JNIEXPORT void JNICALL
+Java_NoClassDefFoundMsg_callFindClass(JNIEnv *env, jclass klass, jstring className) {
+    const char *c_name;
+    jclass cls;
+    if (className == NULL) {
+        c_name = NULL;
+    } else {
+        c_name = (*env)->GetStringUTFChars(env, className, NULL);
+    }
+    cls = (*env)->FindClass(env, c_name);
+}
+
+