diff --git a/src/com/hellhole/hhsoj/tomcat/servlet/RebaseServlet.java b/src/com/hellhole/hhsoj/tomcat/servlet/RebaseServlet.java
index b6768cf..92fb4e8 100644
--- a/src/com/hellhole/hhsoj/tomcat/servlet/RebaseServlet.java
+++ b/src/com/hellhole/hhsoj/tomcat/servlet/RebaseServlet.java
@@ -11,11 +11,7 @@
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
-import com.google.gson.Gson;
-import com.hellhole.hhsoj.common.FileUtil;
-import com.hellhole.hhsoj.common.Problem;
 import com.hellhole.hhsoj.common.Problemset;
-import com.hellhole.hhsoj.common.Submission;
 import com.hellhole.hhsoj.tomcat.util.TomcatHelper;
 
 /**