public java.lang.StringBuffer delete(int start,int end){
  internal.delete(start,end);
  return this;
}

public java . lang . StringBuffer delete ( int start , int end ) { internal . delete ( start , end ) ; return this ; }
removes the characters in a substring of this stringbuffer . the substring begins at the specified start and extends to the character at index end - 1 or to the end of the stringbuffer if no such character exists . if start is equal to end , no changes are made .
