I cant find any sorting function in the java API for vectors.
Collections.sort is only for List and not for Vector.<
According to the Java API Specification for the Vector class, it implements the List interface which is needed to use the Collections.sort method.
Also, as a note, for most uses the Vector class could be replaced by using one of the List implementations in the Java Collections Framework, such as ArrayList. The Vector class is synchronized, so unless there is a real need for synchronized access one should use one of the other List implementations.