code: import java.io.BufferedReader;
  import java.io.BufferedWriter;
  import java.io.IOException;
  
  
  public class Example {
  
  	int label;
  	SparseVector sv;
  	
  	public Example(int label, SparseVector sv) {
  	    this.label = label;
  	    this.sv = sv;
  	}
  	
  	private static String readLineSkip(BufferedReader in) throws IOException {
  	    String line = null;
  	    while ((line = in.readLine())!= null) {
  	        line = line.trim();
  	        if (!line.equals("") && !line.startsWith("#")) {
  	            break; 
  	        }
  	    }
  	    return line;
  	    
  	}
  	
  	public static Example readExample(BufferedReader in) throws IOException {
  	    String line = readLineSkip(in);
  	    if (line == null) {
  	        return null;
  	    }
  	    
  	    line = line.trim();
  	    String rec = line.split("\\s")[0];
  	    
  	    int label = Integer.parseInt(rec);
  	    String vector = "";
  	    if (line.length() > rec.length()) {
  	        vector = line.substring(rec.length() + 1);
  	    }
  	    SparseVector sv = SparseVector.load(vector);
  	    return new Example(label, sv);
  	}
  	
  	public void saveExample(BufferedWriter out) throws IOException {
  	    out.write(label + " " + sv.save() + System.getProperty("line.separator"));
  	}
  
      @Override
      public String toString() {
          return "Example [label=" + label + ", sv=" + sv + "]";
      }
  	
  	
  }
  