More native code cleanup.

Don't keep unused global references to classes, don't throw exceptions
when an exception is already pending, and fix a (harmless) misunderstanding
about how GetStringChars works.

Change-Id: Ie445036f057daa8a1c76aceb7bad2a84fb81d820
diff --git a/core/jni/android_net_NetUtils.cpp b/core/jni/android_net_NetUtils.cpp
index db132ec..4a0e68e 100644
--- a/core/jni/android_net_NetUtils.cpp
+++ b/core/jni/android_net_NetUtils.cpp
@@ -1,16 +1,16 @@
 /*
  * Copyright 2008, The Android Open Source Project
  *
- * Licensed under the Apache License, Version 2.0 (the "License"); 
- * you may not use this file except in compliance with the License. 
- * You may obtain a copy of the License at 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     http://www.apache.org/licenses/LICENSE-2.0 
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * Unless required by applicable law or agreed to in writing, software 
- * distributed under the License is distributed on an "AS IS" BASIS, 
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
- * See the License for the specific language governing permissions and 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
@@ -225,9 +225,6 @@
 
 int register_android_net_NetworkUtils(JNIEnv* env)
 {
-    jclass netutils = env->FindClass(NETUTILS_PKG_NAME);
-    LOG_FATAL_IF(netutils == NULL, "Unable to find class " NETUTILS_PKG_NAME);
-
     jclass dhcpInfoInternalClass = env->FindClass("android/net/DhcpInfoInternal");
     LOG_FATAL_IF(dhcpInfoInternalClass == NULL, "Unable to find class android/net/DhcpInfoInternal");
     dhcpInfoInternalFieldIds.constructorId = env->GetMethodID(dhcpInfoInternalClass, "<init>", "()V");