diff --git a/src/main/java/org/sonarsource/plugins/mybatis/Constant.java b/src/main/java/org/sonarsource/plugins/mybatis/Constant.java
index e808b9b..b8b4993 100644
--- a/src/main/java/org/sonarsource/plugins/mybatis/Constant.java
+++ b/src/main/java/org/sonarsource/plugins/mybatis/Constant.java
@@ -1,12 +1,12 @@
 package org.sonarsource.plugins.mybatis;
 
 public class Constant {
-    public static String MYBATIS_MAPPER_CHECK_RULE_01 = "MyBatisMapperCheckRule01";
-    public static String MYBATIS_MAPPER_CHECK_RULE_02 = "MyBatisMapperCheckRule02";
-    public static String MYBATIS_MAPPER_CHECK_RULE_03 = "MyBatisMapperCheckRule03";
-    public static String MYBATIS_MAPPER_CHECK_RULE_04 = "MyBatisMapperCheckRule04";
-    public static String MYBATIS_MAPPER_CHECK_RULE_05 = "MyBatisMapperCheckRule05";
-    public static String MYBATIS_MAPPER_CHECK_RULE_06 = "MyBatisMapperCheckRule06";
-    public static String MYBATIS_MAPPER_CHECK_RULE_07 = "MyBatisMapperCheckRule07";
+    public static final String MYBATIS_MAPPER_CHECK_RULE_01 = "MyBatisMapperCheckRule01";
+    public static final String MYBATIS_MAPPER_CHECK_RULE_02 = "MyBatisMapperCheckRule02";
+    public static final String MYBATIS_MAPPER_CHECK_RULE_03 = "MyBatisMapperCheckRule03";
+    public static final String MYBATIS_MAPPER_CHECK_RULE_04 = "MyBatisMapperCheckRule04";
+    public static final String MYBATIS_MAPPER_CHECK_RULE_05 = "MyBatisMapperCheckRule05";
+    public static final String MYBATIS_MAPPER_CHECK_RULE_06 = "MyBatisMapperCheckRule06";
+    public static final String MYBATIS_MAPPER_CHECK_RULE_07 = "MyBatisMapperCheckRule07";
 
 }