diff --git a/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp b/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp
index 0a8aabf4f57d3c2225a88c97df2f2b143fc4eac1..42284edd14bc9d28f573ed77328c9906becdad46 100644
--- a/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp
+++ b/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2011, The Android Open Source Project
+ * Copyright (C) 2011, 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.
diff --git a/native/jni/com_android_inputmethod_keyboard_ProximityInfo.h b/native/jni/com_android_inputmethod_keyboard_ProximityInfo.h
index f5ccf20536dbb9ae424aa34b9d204e6d9c9063a1..51fa895d3c3daa5a5fd816e421a5ee0af84295be 100644
--- a/native/jni/com_android_inputmethod_keyboard_ProximityInfo.h
+++ b/native/jni/com_android_inputmethod_keyboard_ProximityInfo.h
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2011, The Android Open Source Project
+ * Copyright (C) 2011, 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.
diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
index 8725b0c9d2b09c45bf194757da56ec439c3b9e46..71bef937d112a766c5ac4ee63f3beb89d7ae0dad 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2009, The Android Open Source Project
+ * Copyright (C) 2009, 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.
diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.h b/native/jni/com_android_inputmethod_latin_BinaryDictionary.h
index 0b67e6b952b74aec614cd7e74ab7d830e561b3b7..b9e944f07062fa192a25478a03d2015fd5c9616e 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.h
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.h
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2011, The Android Open Source Project
+ * Copyright (C) 2011, 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.
diff --git a/native/jni/com_android_inputmethod_latin_NativeUtils.cpp b/native/jni/com_android_inputmethod_latin_NativeUtils.cpp
index 32d895405b789be495bcb14043fd18cbf20ac121..9aae81716616224829768be63bd9688197688066 100644
--- a/native/jni/com_android_inputmethod_latin_NativeUtils.cpp
+++ b/native/jni/com_android_inputmethod_latin_NativeUtils.cpp
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2012, The Android Open Source Project
+ * Copyright (C) 2012, 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.
diff --git a/native/jni/com_android_inputmethod_latin_NativeUtils.h b/native/jni/com_android_inputmethod_latin_NativeUtils.h
index 4d29d7d472365a2857da7cabf8f971e0f2412a86..d1ffb8f4a436941c091438c4109f1dd1d1f860ec 100644
--- a/native/jni/com_android_inputmethod_latin_NativeUtils.h
+++ b/native/jni/com_android_inputmethod_latin_NativeUtils.h
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2012, The Android Open Source Project
+ * Copyright (C) 2012, 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.
diff --git a/native/jni/jni_common.cpp b/native/jni/jni_common.cpp
index 8d7bce79e89507a22cc373150caa95a24cdb3ddb..4eeda1d4e0904a9726be1cdf2c59ad12f0edc85d 100644
--- a/native/jni/jni_common.cpp
+++ b/native/jni/jni_common.cpp
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2011, The Android Open Source Project
+ * Copyright (C) 2011, 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.
@@ -37,11 +36,11 @@ jint JNI_OnLoad(JavaVM *vm, void *reserved) {
     JNIEnv *env = 0;
     jint result = -1;
 
-    if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {
+    if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
         AKLOGE("ERROR: GetEnv failed");
         goto bail;
     }
-    assert(env != 0);
+    assert(env);
 
     if (!register_BinaryDictionary(env)) {
         AKLOGE("ERROR: BinaryDictionary native registration failed");
@@ -59,7 +58,7 @@ jint JNI_OnLoad(JavaVM *vm, void *reserved) {
     }
 
     /* success -- return valid version number */
-    result = JNI_VERSION_1_4;
+    result = JNI_VERSION_1_6;
 
 bail:
     return result;
@@ -70,7 +69,7 @@ namespace latinime {
 int registerNativeMethods(JNIEnv *env, const char *className, JNINativeMethod *methods,
         int numMethods) {
     jclass clazz = env->FindClass(className);
-    if (clazz == 0) {
+    if (!clazz) {
         AKLOGE("Native registration unable to find class '%s'", className);
         return JNI_FALSE;
     }
diff --git a/native/jni/jni_common.h b/native/jni/jni_common.h
index 32f9fa9b8a1ab00518ca4895f0dc2ae8a0e8d3c1..771361d5e9ea8f6e2448002f0a426f710d07255d 100644
--- a/native/jni/jni_common.h
+++ b/native/jni/jni_common.h
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2011, The Android Open Source Project
+ * Copyright (C) 2011, 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.
diff --git a/native/jni/src/bigram_dictionary.cpp b/native/jni/src/bigram_dictionary.cpp
index 4f5493ad17fb3e7becf346ea492a8f492e10f163..8dc212203b66998ab314fccf687786490644ce63 100644
--- a/native/jni/src/bigram_dictionary.cpp
+++ b/native/jni/src/bigram_dictionary.cpp
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2010, The Android Open Source Project
+ * Copyright (C) 2010, 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.
diff --git a/native/jni/src/debug.h b/native/jni/src/debug.h
index 2fee6e83fe023cf6e384ccab9d9a7136eab7b3d0..2168d66723f779e884298d68615bc604dc3a0f16 100644
--- a/native/jni/src/debug.h
+++ b/native/jni/src/debug.h
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2011, The Android Open Source Project
+ * Copyright (C) 2011, 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.
diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index 05b997d5939409b272109a8b2ed03a2eb6040fca..e172b0441d70740dae042986fcc54bfb31485b2f 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2010, The Android Open Source Project
+ * Copyright (C) 2010, 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.
@@ -96,7 +95,7 @@ static inline void prof_out(void) {
     }
     if (all == 0) all = 1;
     for (int i = 0; i < PROF_BUF_SIZE - 1; ++i) {
-        if (profile_buf[i] != 0) {
+        if (profile_buf[i]) {
             AKLOGI("(%d): Used %4.2f%%, %8.4f ms. Called %d times.",
                     i, (profile_buf[i] * 100 / all),
                     profile_buf[i] * 1000 / (float)CLOCKS_PER_SEC, profile_counter[i]);
diff --git a/native/jni/src/dictionary.cpp b/native/jni/src/dictionary.cpp
index 4703a38e8d2ec481e80517ea06eb92a0ad0eaa87..dabd98b5f136160b31ae00abf6162c4c354d0975 100644
--- a/native/jni/src/dictionary.cpp
+++ b/native/jni/src/dictionary.cpp
@@ -1,5 +1,4 @@
 /*
- *
  * Copyright (C) 2009, The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/native/jni/src/unigram_dictionary.cpp b/native/jni/src/unigram_dictionary.cpp
index b121d08a8e45d2a8f8765545bd3d6213ef113cb0..ce3108b3b0d03750debddd9ebfcce523da705b0e 100644
--- a/native/jni/src/unigram_dictionary.cpp
+++ b/native/jni/src/unigram_dictionary.cpp
@@ -1,6 +1,5 @@
 /*
- *
- * Copyright 2010, The Android Open Source Project
+ * Copyright (C) 2010, 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.