diff --git a/src/main/java/org/gcube/socialnetworking/socialtoken/SanitizedURL.java b/src/main/java/org/gcube/socialnetworking/socialtoken/SanitizedURL.java
index 454c257..7754917 100644
--- a/src/main/java/org/gcube/socialnetworking/socialtoken/SanitizedURL.java
+++ b/src/main/java/org/gcube/socialnetworking/socialtoken/SanitizedURL.java
@@ -12,6 +12,10 @@ public class SanitizedURL {
 	protected final URL url;
 	
 	public SanitizedURL(String urlString) throws MalformedURLException {
+		if(urlString==null || urlString.compareTo("")==0) {
+			throw new MalformedURLException();
+		}
+		
 		prefix = "";
 		if(urlString.startsWith("(")) {
 			prefix = urlString.substring(0, 1);
diff --git a/src/test/java/org/gcube/social_networking/socialutillibrary/MessageParserTest.java b/src/test/java/org/gcube/social_networking/socialutillibrary/MessageParserTest.java
index b11a93a..f7dd3f8 100644
--- a/src/test/java/org/gcube/social_networking/socialutillibrary/MessageParserTest.java
+++ b/src/test/java/org/gcube/social_networking/socialutillibrary/MessageParserTest.java
@@ -1,9 +1,11 @@
 package org.gcube.social_networking.socialutillibrary;
 
+import java.net.MalformedURLException;
 import java.util.ArrayList;
 import java.util.List;
 
 import org.gcube.portlets.widgets.pickitem.shared.ItemBean;
+import org.gcube.socialnetworking.socialtoken.SanitizedURL;
 import org.gcube.socialnetworking.socialtoken.SocialMessageParser;
 import org.junit.Test;
 import org.slf4j.Logger;
@@ -91,4 +93,9 @@ public class MessageParserTest {
 		logger.debug(messageParser.getParsedMessage());
 		
 	}
+	
+	@Test(expected=MalformedURLException.class)
+	public void auxTest() throws MalformedURLException {
+		new SanitizedURL(null);		
+	}
 }