diff --git a/src/main/java/com/nexacro/spring/NexacroException.java b/src/main/java/com/nexacro/spring/NexacroException.java
index 7e6f0d9..b962413 100644
--- a/src/main/java/com/nexacro/spring/NexacroException.java
+++ b/src/main/java/com/nexacro/spring/NexacroException.java
@@ -24,7 +24,7 @@ public class NexacroException extends Exception {
     public static final String DEFAULT_MESSAGE = "An Error Occured. check the ErrorCode for detail of error infomation.";
 
     private int errorCode = DEFAULT_ERROR_CODE;
-    private String errorMsg = DEFAULT_MESSAGE;
+    private String errorMsg;
 
     /**
      * 기본 생성자이다.
diff --git a/src/main/java/com/nexacro/spring/annotation/ParamDataSet.java b/src/main/java/com/nexacro/spring/annotation/ParamDataSet.java
index ca0bee3..659cbd4 100644
--- a/src/main/java/com/nexacro/spring/annotation/ParamDataSet.java
+++ b/src/main/java/com/nexacro/spring/annotation/ParamDataSet.java
@@ -5,8 +5,6 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import com.nexacro.spring.context.NexacroContextHolder;
-
 /**
  * <p><code>DataSet</code>을 List혹은 POJO형태의 데이터로 변환을 수행하기 위한 annotation이다.
  * 
@@ -17,15 +15,23 @@ import com.nexacro.spring.context.NexacroContextHolder;
  * @author Park SeongMin
  * @since 07.28.2015
  * @version 1.0
- * @see NexacroContextHolder
+ * @see ParamVariable
  */
 @Target({ java.lang.annotation.ElementType.PARAMETER })
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 public @interface ParamDataSet {
 	/**
-	 * 데이터셋의 식별자
+	 * <code>DataSet</code>의 식별자
 	 * @return dsName
 	 */
-	public abstract String name();
+	String name();
+	
+	/**
+	 * Whether the parameter is required.
+	 * <p>Default is {@code true}, leading to an exception thrown in case
+	 * of the parameter missing in the request. Switch this to {@code false}
+	 * if you prefer a {@code null} in case of the parameter missing.
+	 */
+	boolean required() default true;
 }
\ No newline at end of file
diff --git a/src/main/java/com/nexacro/spring/annotation/ParamVariable.java b/src/main/java/com/nexacro/spring/annotation/ParamVariable.java
index f610edc..a2202ec 100644
--- a/src/main/java/com/nexacro/spring/annotation/ParamVariable.java
+++ b/src/main/java/com/nexacro/spring/annotation/ParamVariable.java
@@ -5,8 +5,6 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import com.nexacro.spring.context.NexacroContextHolder;
-
 /**
  * <p><code>Variable</code>을 Primitive 형태의 데이터로 변환을 수행하기 위한 annotation이다.
  * 
@@ -17,11 +15,24 @@ import com.nexacro.spring.context.NexacroContextHolder;
  * @author Park SeongMin
  * @since 07.28.2015
  * @version 1.0
- * @see NexacroContextHolder
+ * @see ParamDataSet
  */
 @Target({ java.lang.annotation.ElementType.PARAMETER })
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 public @interface ParamVariable {
-	public abstract String name();
+	
+	/**
+	 * <code>Variable</code>식별자
+	 * @return dsName
+	 */
+	String name();
+	
+	/**
+	 * Whether the parameter is required.
+	 * <p>Default is {@code true}, leading to an exception thrown in case
+	 * of the parameter missing in the request. Switch this to {@code false}
+	 * if you prefer a {@code null} in case of the parameter missing.
+	 */
+	boolean required() default true;
 }
\ No newline at end of file
diff --git a/src/main/java/com/nexacro/spring/resolve/NexacroMethodArgumentResolver.java b/src/main/java/com/nexacro/spring/resolve/NexacroMethodArgumentResolver.java
index caae50b..4109dc3 100644
--- a/src/main/java/com/nexacro/spring/resolve/NexacroMethodArgumentResolver.java
+++ b/src/main/java/com/nexacro/spring/resolve/NexacroMethodArgumentResolver.java
@@ -6,6 +6,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
@@ -13,6 +14,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.core.MethodParameter;
 import org.springframework.util.StopWatch;
+import org.springframework.web.bind.MissingServletRequestParameterException;
 import org.springframework.web.bind.support.WebDataBinderFactory;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.RequestAttributes;
@@ -275,9 +277,12 @@ public class NexacroMethodArgumentResolver implements HandlerMethodArgumentResol
         String dsName = paramDataSet.name();
         DataSet dataSet = nexacroCachedData.getPlatformData().getDataSet(dsName);
         if(dataSet == null) {
-            if(logger.isDebugEnabled()) {
+        	if(logger.isDebugEnabled()) {
                 logger.debug("@ParamDataSet '" + dsName + "' argument is null.");
             }
+        	if (paramDataSet.required()) {
+				handleMissingValue(paramDataSet.name(), param);
+			}
             return null;
         }
         
@@ -330,6 +335,9 @@ public class NexacroMethodArgumentResolver implements HandlerMethodArgumentResol
             if(logger.isDebugEnabled()) {
             	logger.debug("@ParamVariable '" + varName + "' argument is null.");
             }
+            if (paramVariable.required()) {
+				handleMissingValue(paramVariable.name(), param);
+			}
             return null;
             //throw new IllegalArgumentException("invalid @ParamVariable. ex)@ParamVariable(name=\"variableName\") Object var");
         }
@@ -382,6 +390,10 @@ public class NexacroMethodArgumentResolver implements HandlerMethodArgumentResol
         return null;
     }
     
+	protected void handleMissingValue(String name, MethodParameter parameter) throws NexacroConvertException {
+		throw new MissingNexacroParameterException(name, parameter.getParameterType().getSimpleName());
+	}
+    
     private Object getAttribute(NativeWebRequest nativeWebRequest, String attrName) {
         return nativeWebRequest.getAttribute(attrName, RequestAttributes.SCOPE_REQUEST);
     }