code: public void setChromosome(String chr) throws Exception {
  		if ( twoBitParser == null){
  
  		}
  		twoBitParser.close();
  		String[] names = twoBitParser.getSequenceNames();
  		for(int i=0;i<names.length;i++) {
  			if ( names[i].equalsIgnoreCase(chr) ) {
  				twoBitParser.setCurrentSequence(names[i]);
  				break;
  			}
  		}
  	}
docs: Sets a chromosome for TwoBitParser.
  
  @param chr The chromosome name (e.g. chr21)