diff --git a/src/dalvik_system_DexFile.cc b/src/dalvik_system_DexFile.cc
index a255141..713639f 100644
--- a/src/dalvik_system_DexFile.cc
+++ b/src/dalvik_system_DexFile.cc
@@ -124,7 +124,8 @@
   delete dex_file;
 }
 
-jclass DexFile_defineClass(JNIEnv* env, jclass, jstring javaName, jobject javaLoader, jint cookie) {
+jclass DexFile_defineClassNative(JNIEnv* env, jclass, jstring javaName, jobject javaLoader,
+                                 jint cookie) {
   ScopedThreadStateChange tsc(Thread::Current(), Thread::kRunnable);
   const DexFile* dex_file = toDexFile(env, cookie);
   if (dex_file == NULL) {
@@ -145,20 +146,6 @@
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
   class_linker->RegisterDexFile(*dex_file);
   Class* result = class_linker->DefineClass(descriptor, class_loader, *dex_file, *dex_class_def);
-  if (env->ExceptionCheck()) {
-    // Swallow any ClassNotFoundException or NoClassDefFoundError; the contract with the caller
-    // is that we return null if the class is not found.
-    jthrowable exception = env->ExceptionOccurred();
-    env->ExceptionClear();
-
-    static jclass ClassNotFoundException_class = CacheClass(env, "java/lang/ClassNotFoundException");
-    static jclass NoClassDefFoundError_class = CacheClass(env, "java/lang/NoClassDefFoundError");
-
-    if (!env->IsInstanceOf(exception, ClassNotFoundException_class) && !env->IsInstanceOf(exception, NoClassDefFoundError_class)) {
-      env->Throw(exception);
-    }
-    return NULL;
-  }
   return AddLocalReference<jclass>(env, result);
 }
 
@@ -223,7 +210,7 @@
 
 static JNINativeMethod gMethods[] = {
   NATIVE_METHOD(DexFile, closeDexFile, "(I)V"),
-  NATIVE_METHOD(DexFile, defineClass, "(Ljava/lang/String;Ljava/lang/ClassLoader;I)Ljava/lang/Class;"),
+  NATIVE_METHOD(DexFile, defineClassNative, "(Ljava/lang/String;Ljava/lang/ClassLoader;I)Ljava/lang/Class;"),
   NATIVE_METHOD(DexFile, getClassNameList, "(I)[Ljava/lang/String;"),
   NATIVE_METHOD(DexFile, isDexOptNeeded, "(Ljava/lang/String;)Z"),
   NATIVE_METHOD(DexFile, openDexFile, "(Ljava/lang/String;Ljava/lang/String;I)I"),
diff --git a/src/debugger.cc b/src/debugger.cc
index 4c47e00..40405eb 100644
--- a/src/debugger.cc
+++ b/src/debugger.cc
@@ -612,13 +612,14 @@
   return 0;
 }
 
-bool Dbg::GetSignature(JDWP::RefTypeId refTypeId, std::string& signature) {
-  Object* o = gRegistry->Get<Object*>(refTypeId);
-  if (o == NULL || !o->IsClass()) {
-    return false;
+JDWP::JdwpError Dbg::GetSignature(JDWP::RefTypeId refTypeId, std::string& signature) {
+  JDWP::JdwpError status;
+  Class* c = DecodeClass(refTypeId, status);
+  if (c == NULL) {
+    return status;
   }
-  signature = ClassHelper(o->AsClass()).GetDescriptor();
-  return true;
+  signature = ClassHelper(c).GetDescriptor();
+  return JDWP::ERR_NONE;
 }
 
 bool Dbg::GetSourceFile(JDWP::RefTypeId refTypeId, std::string& result) {
diff --git a/src/debugger.h b/src/debugger.h
index b92fbfe..8a702a1 100644
--- a/src/debugger.h
+++ b/src/debugger.h
@@ -140,7 +140,7 @@
   static void FindLoadedClassBySignature(const char* descriptor, std::vector<JDWP::RefTypeId>& ids);
   static void GetObjectType(JDWP::ObjectId objectId, JDWP::JdwpTypeTag* pRefTypeTag, JDWP::RefTypeId* pRefTypeId);
   static uint8_t GetClassObjectType(JDWP::RefTypeId refTypeId);
-  static bool GetSignature(JDWP::RefTypeId refTypeId, std::string& signature);
+  static JDWP::JdwpError GetSignature(JDWP::RefTypeId refTypeId, std::string& signature);
   static bool GetSourceFile(JDWP::RefTypeId refTypeId, std::string& source_file);
   static uint8_t GetObjectTag(JDWP::ObjectId objectId);
   static size_t GetTagWidth(JDWP::JdwpTag tag);
diff --git a/src/jdwp/jdwp_handler.cc b/src/jdwp/jdwp_handler.cc
index 5e4487c..99916bd 100644
--- a/src/jdwp/jdwp_handler.cc
+++ b/src/jdwp/jdwp_handler.cc
@@ -416,10 +416,7 @@
   return ERR_NONE;
 }
 
-/*
- * Cough up the complete list of classes.
- */
-static JdwpError handleVM_AllClassesWithGeneric(JdwpState* state, const uint8_t* buf, int dataLen, ExpandBuf* pReply) {
+static JdwpError handleVM_AllClasses(JdwpState* state, const uint8_t* buf, int dataLen, ExpandBuf* pReply, bool generic) {
   std::vector<JDWP::RefTypeId> classes;
   Dbg::GetClassList(classes);
 
@@ -437,13 +434,23 @@
     expandBufAdd1(pReply, refTypeTag);
     expandBufAddRefTypeId(pReply, classes[i]);
     expandBufAddUtf8String(pReply, descriptor);
-    expandBufAddUtf8String(pReply, genericSignature);
+    if (generic) {
+      expandBufAddUtf8String(pReply, genericSignature);
+    }
     expandBufAdd4BE(pReply, status);
   }
 
   return ERR_NONE;
 }
 
+static JdwpError handleVM_AllClasses(JdwpState* state, const uint8_t* buf, int dataLen, ExpandBuf* pReply) {
+  return handleVM_AllClasses(state, buf, dataLen, pReply, false);
+}
+
+static JdwpError handleVM_AllClassesWithGeneric(JdwpState* state, const uint8_t* buf, int dataLen, ExpandBuf* pReply) {
+  return handleVM_AllClasses(state, buf, dataLen, pReply, true);
+}
+
 /*
  * Given a referenceTypeID, return a string with the JNI reference type
  * signature (e.g. "Ljava/lang/Error;").
@@ -453,8 +460,10 @@
 
   VLOG(jdwp) << StringPrintf("  Req for signature of refTypeId=0x%llx", refTypeId);
   std::string signature;
-  if (!Dbg::GetSignature(refTypeId, signature)) {
-    return ERR_INVALID_CLASS;
+
+  JdwpError status = Dbg::GetSignature(refTypeId, signature);
+  if (status != ERR_NONE) {
+    return status;
   }
   expandBufAddUtf8String(pReply, signature);
   return ERR_NONE;
@@ -1563,7 +1572,7 @@
   /* VirtualMachine command set (1) */
   { 1,    1,  handleVM_Version,       "VirtualMachine.Version" },
   { 1,    2,  handleVM_ClassesBySignature, "VirtualMachine.ClassesBySignature" },
-  { 1,    3,  NULL, "VirtualMachine.AllClasses" },
+  { 1,    3,  handleVM_AllClasses,    "VirtualMachine.AllClasses" },
   { 1,    4,  handleVM_AllThreads,    "VirtualMachine.AllThreads" },
   { 1,    5,  handleVM_TopLevelThreadGroups, "VirtualMachine.TopLevelThreadGroups" },
   { 1,    6,  handleVM_Dispose,       "VirtualMachine.Dispose" },