diff --git a/java/src/com/android/inputmethod/latin/define/JniLibName.java b/java/src/com/android/inputmethod/latin/define/JniLibName.java
index 3e94a3c..e23e1a9 100644
--- a/java/src/com/android/inputmethod/latin/define/JniLibName.java
+++ b/java/src/com/android/inputmethod/latin/define/JniLibName.java
@@ -16,6 +16,10 @@
 
 package com.android.inputmethod.latin.define;
 
-public class JniLibName {
+public final class JniLibName {
+    private JniLibName() {
+        // This class is not publicly instantiable.
+    }
+
     public static final String JNI_LIB_NAME = "jni_latinime";
 }
diff --git a/java/src/com/android/inputmethod/latin/define/ProductionFlag.java b/java/src/com/android/inputmethod/latin/define/ProductionFlag.java
index cfb1d09..de20576 100644
--- a/java/src/com/android/inputmethod/latin/define/ProductionFlag.java
+++ b/java/src/com/android/inputmethod/latin/define/ProductionFlag.java
@@ -16,6 +16,10 @@
 
 package com.android.inputmethod.latin.define;
 
-public class ProductionFlag {
+public final class ProductionFlag {
+    private ProductionFlag() {
+        // This class is not publicly instantiable.
+    }
+
     public static final boolean IS_EXPERIMENTAL = false;
 }