Optimize imports

wicket/src/main/java/hellowicket/World.java

@@ -1,8 +1,9 @@
 package hellowicket;
 
-import java.util.*;
-
-import javax.persistence.*;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
 
 @Entity
 public class World