Update version number.
diff --git a/java/util/pom.xml b/java/util/pom.xml
index 56a4e52..6b07bcd 100644
--- a/java/util/pom.xml
+++ b/java/util/pom.xml
@@ -6,7 +6,7 @@
   <parent>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-parent</artifactId>
-    <version>3.1.0-alpha-1</version>
+    <version>3.1.0</version>
   </parent>
 
   <artifactId>protobuf-java-util</artifactId>