Logical Compiler Error [on hold]

 public String frontBack(String str) {
 String last;
 String first;
 last = str.substring(str.length() - 1);
 first = str.substring(0, 1);
   if(str.length() == 1)
    return str ;
   else if(str.length() == 2)
    return last + first ;
   else(str.length() > 2)
    return last + str.substring(1, str.length() - 2) + first;
}

Why am I receiving the following error?

Error:  else(str.length() > 2)
                     ^
Syntax error, insert "AssignmentOperator ArrayInitializer" to complete ArrayInitializerAssignement``