Why cant we use .append with string object in java? :        import java.lang.StringBuffer.*;
       import java.io.*;

       class chk
       {
       public static void main() 
       {
       
       System.out.print('\u000c');
   
    
        String k="catering";

             *    String l=k.append(5); (shows error here)
  
 
       System.out.println(l);
      
       }
       }

i cant understand why it is showing an error?? is it that we cant access methods from other class(ex.Stringbuffer class) from string class?? plz help!!