public BubbleXYItemLabelGenerator(){
  this(DEFAULT_FORMAT_STRING,NumberFormat.getNumberInstance(),NumberFormat.getNumberInstance(),NumberFormat.getNumberInstance());
}

public BubbleXYItemLabelGenerator ( ) { this ( DEFAULT_FORMAT_STRING , NumberFormat . getNumberInstance ( ) , NumberFormat . getNumberInstance ( ) , NumberFormat . getNumberInstance ( ) ) ; }
creates a new tool tip generator using default number formatters for the x , y and z - values .
