diff --git a/src/main/java/org/apache/ibatis/annotations/Lang.java b/src/main/java/org/apache/ibatis/annotations/Lang.java
index b23c1c7c430..696bb520ee4 100644
--- a/src/main/java/org/apache/ibatis/annotations/Lang.java
+++ b/src/main/java/org/apache/ibatis/annotations/Lang.java
@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2016 the original author or authors.
+ *    Copyright 2009-2018 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
  */
 package org.apache.ibatis.annotations;
 
+import org.apache.ibatis.scripting.LanguageDriver;
+
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
@@ -28,5 +30,5 @@
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)
 public @interface Lang {
-  Class<?> value();
+  Class<? extends LanguageDriver> value();
 }
diff --git a/src/main/java/org/apache/ibatis/builder/BaseBuilder.java b/src/main/java/org/apache/ibatis/builder/BaseBuilder.java
index 76c50cae94e..8bcf7109f5b 100644
--- a/src/main/java/org/apache/ibatis/builder/BaseBuilder.java
+++ b/src/main/java/org/apache/ibatis/builder/BaseBuilder.java
@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2015 the original author or authors.
+ *    Copyright 2009-2018 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -108,7 +108,7 @@ protected Object createInstance(String alias) {
     }
   }
 
-  protected Class<?> resolveClass(String alias) {
+  protected <T> Class<? extends T> resolveClass(String alias) {
     if (alias == null) {
       return null;
     }
@@ -145,7 +145,7 @@ protected TypeHandler<?> resolveTypeHandler(Class<?> javaType, Class<? extends T
     return handler;
   }
 
-  protected Class<?> resolveAlias(String alias) {
+  protected <T> Class<? extends T> resolveAlias(String alias) {
     return typeAliasRegistry.resolveAlias(alias);
   }
 }
diff --git a/src/main/java/org/apache/ibatis/builder/MapperBuilderAssistant.java b/src/main/java/org/apache/ibatis/builder/MapperBuilderAssistant.java
index f30bdc421f4..43121881eb4 100644
--- a/src/main/java/org/apache/ibatis/builder/MapperBuilderAssistant.java
+++ b/src/main/java/org/apache/ibatis/builder/MapperBuilderAssistant.java
@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2017 the original author or authors.
+ *    Copyright 2009-2018 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -472,7 +472,7 @@ public ResultMapping buildResultMapping(
         nestedResultMap, notNullColumn, columnPrefix, typeHandler, flags, null, null, configuration.isLazyLoadingEnabled());
   }
 
-  public LanguageDriver getLanguageDriver(Class<?> langClass) {
+  public LanguageDriver getLanguageDriver(Class<? extends LanguageDriver> langClass) {
     if (langClass != null) {
       configuration.getLanguageRegistry().register(langClass);
     } else {
diff --git a/src/main/java/org/apache/ibatis/builder/annotation/MapperAnnotationBuilder.java b/src/main/java/org/apache/ibatis/builder/annotation/MapperAnnotationBuilder.java
index c8a19cc0e34..954d0330322 100644
--- a/src/main/java/org/apache/ibatis/builder/annotation/MapperAnnotationBuilder.java
+++ b/src/main/java/org/apache/ibatis/builder/annotation/MapperAnnotationBuilder.java
@@ -383,7 +383,7 @@ void parseStatement(Method method) {
   
   private LanguageDriver getLanguageDriver(Method method) {
     Lang lang = method.getAnnotation(Lang.class);
-    Class<?> langClass = null;
+    Class<? extends LanguageDriver> langClass = null;
     if (lang != null) {
       langClass = lang.value();
     }
diff --git a/src/main/java/org/apache/ibatis/builder/xml/XMLStatementBuilder.java b/src/main/java/org/apache/ibatis/builder/xml/XMLStatementBuilder.java
index ddc7663a643..623eca94e16 100644
--- a/src/main/java/org/apache/ibatis/builder/xml/XMLStatementBuilder.java
+++ b/src/main/java/org/apache/ibatis/builder/xml/XMLStatementBuilder.java
@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2017 the original author or authors.
+ *    Copyright 2009-2018 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -192,7 +192,7 @@ private boolean databaseIdMatchesCurrent(String id, String databaseId, String re
   }
 
   private LanguageDriver getLanguageDriver(String lang) {
-    Class<?> langClass = null;
+    Class<? extends LanguageDriver> langClass = null;
     if (lang != null) {
       langClass = resolveClass(lang);
     }
diff --git a/src/main/java/org/apache/ibatis/scripting/LanguageDriverRegistry.java b/src/main/java/org/apache/ibatis/scripting/LanguageDriverRegistry.java
index f981e55fde7..a8196cd0138 100644
--- a/src/main/java/org/apache/ibatis/scripting/LanguageDriverRegistry.java
+++ b/src/main/java/org/apache/ibatis/scripting/LanguageDriverRegistry.java
@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2017 the original author or authors.
+ *    Copyright 2009-2018 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -23,17 +23,17 @@
  */
 public class LanguageDriverRegistry {
 
-  private final Map<Class<?>, LanguageDriver> LANGUAGE_DRIVER_MAP = new HashMap<Class<?>, LanguageDriver>();
+  private final Map<Class<? extends LanguageDriver>, LanguageDriver> LANGUAGE_DRIVER_MAP = new HashMap<>();
 
-  private Class<?> defaultDriverClass;
+  private Class<? extends LanguageDriver> defaultDriverClass;
 
-  public void register(Class<?> cls) {
+  public void register(Class<? extends LanguageDriver> cls) {
     if (cls == null) {
       throw new IllegalArgumentException("null is not a valid Language Driver");
     }
     if (!LANGUAGE_DRIVER_MAP.containsKey(cls)) {
       try {
-        LANGUAGE_DRIVER_MAP.put(cls, (LanguageDriver) cls.newInstance());
+        LANGUAGE_DRIVER_MAP.put(cls, cls.newInstance());
       } catch (Exception ex) {
         throw new ScriptingException("Failed to load language driver for " + cls.getName(), ex);
       }
@@ -44,13 +44,13 @@ public void register(LanguageDriver instance) {
     if (instance == null) {
       throw new IllegalArgumentException("null is not a valid Language Driver");
     }
-    Class<?> cls = instance.getClass();
+    Class<? extends LanguageDriver> cls = instance.getClass();
     if (!LANGUAGE_DRIVER_MAP.containsKey(cls)) {
       LANGUAGE_DRIVER_MAP.put(cls, instance);
     }
   }
   
-  public LanguageDriver getDriver(Class<?> cls) {
+  public LanguageDriver getDriver(Class<? extends LanguageDriver> cls) {
     return LANGUAGE_DRIVER_MAP.get(cls);
   }
 
@@ -58,11 +58,11 @@ public LanguageDriver getDefaultDriver() {
     return getDriver(getDefaultDriverClass());
   }
 
-  public Class<?> getDefaultDriverClass() {
+  public Class<? extends LanguageDriver> getDefaultDriverClass() {
     return defaultDriverClass;
   }
 
-  public void setDefaultDriverClass(Class<?> defaultDriverClass) {
+  public void setDefaultDriverClass(Class<? extends LanguageDriver> defaultDriverClass) {
     register(defaultDriverClass);
     this.defaultDriverClass = defaultDriverClass;
   }
diff --git a/src/main/java/org/apache/ibatis/session/Configuration.java b/src/main/java/org/apache/ibatis/session/Configuration.java
index f2a60fe03f7..bdc4d2d4042 100644
--- a/src/main/java/org/apache/ibatis/session/Configuration.java
+++ b/src/main/java/org/apache/ibatis/session/Configuration.java
@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2017 the original author or authors.
+ *    Copyright 2009-2018 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -520,7 +520,7 @@ public LanguageDriverRegistry getLanguageRegistry() {
     return languageRegistry;
   }
 
-  public void setDefaultScriptingLanguage(Class<?> driver) {
+  public void setDefaultScriptingLanguage(Class<? extends LanguageDriver> driver) {
     if (driver == null) {
       driver = XMLLanguageDriver.class;
     }
diff --git a/src/test/java/org/apache/ibatis/scripting/LanguageDriverRegistryTest.java b/src/test/java/org/apache/ibatis/scripting/LanguageDriverRegistryTest.java
index bbec82c36d8..1ec1f6f4ca1 100644
--- a/src/test/java/org/apache/ibatis/scripting/LanguageDriverRegistryTest.java
+++ b/src/test/java/org/apache/ibatis/scripting/LanguageDriverRegistryTest.java
@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2017 the original author or authors.
+ *    Copyright 2009-2018 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -56,7 +56,7 @@ public void registerByTypeSameType() {
 
   @Test
   public void registerByTypeNull() {
-    when(registry).register((Class<?>) null);
+    when(registry).register((Class<? extends LanguageDriver>) null);
     then(caughtException()).isInstanceOf(IllegalArgumentException.class)
       .hasMessage("null is not a valid Language Driver");
   }