sorting - how to sort and arrange a text file in java to group lines -

really struggling work out...

i have text file data (17000 lines of it)

45226   1 45226   1 45226   1 45226   3 45226   5 23470   1 45226   5 45226   5 29610   4 37417   2 37417   3 37948   1 

what want sort text file (using java) left numbers grouped if right value 1. or left value group if right not equal 1 (so other number). example (but doesn't have this)

3 x 45226   1 4 x 45226   mixed 1 x 23470   1 1 x 29610   mixed 2 x 37417   mixed 1 x 37948   1 

i know may need use array? or sort of sort? can't work out :'(

any help, code or suggestions - appreciated!

thank you!

my code:

public class sort {   private static class counter {      private int one;     private int mixed;      public void incrementone() {         one++;     }      public void incrementmixed() {         mixed++;     } }  public static void main(string[] args) throws ioexception {     map<string, counter> map = new linkedhashmap<string, counter>();     string filename = "input.txt";     bufferedreader reader = new bufferedreader(new filereader(filename));      (string line = reader.readline(); line != null; line = reader.readline()) {         stringtokenizer tokenizer = new stringtokenizer(line);         string key = tokenizer.nexttoken();         string value = tokenizer.nexttoken();         counter counter = map.get(key);         if (counter == null) {             counter = new counter();             map.put(key, counter);         }         if (value.equals("1")) {             counter.incrementone();         } else {             counter.incrementmixed();         }     }     reader.close();     bufferedwriter writer = new bufferedwriter(new filewriter("output.txt"));     for(map.entry<string, counter>entry:map.entryset()){         counter counter = entry.getvalue();         if(counter.one>0){             writer.write(string.valueof(counter.one));             writer.write(" x ");             writer.write(entry.getkey());             writer.write("   1");             writer.newline();         }         if(counter.mixed>0){             writer.write(string.valueof(counter.mixed));             writer.write(" x ");             writer.write(entry.getkey());             writer.write("   mixed");             writer.newline();         }     }     writer.close();  } 

}