This question was asked in an Electronic Arts interview: There are 3 threads. The first thread prints the numbers 1 to 10. The second thread prints the numbers 11 to 20. The third thread prints the numbers from from 21 to 30. Now, all three threads are running. The numbers are printed in an irregular order like 1, 11, 2, 21, 12 etc. If I want numbers to be printed in sorted order like 1, 2, 3, 4..., what should I do with these threads?