Ganesh you will normally get output according to the priority of the threads. But for SCJP you will have to consider all the exceptional cases so you will have to say that the output is unpredictable...
In this case, the threads are so short lived, I highly doubt that priorities are related at all -- it is more of which thread gets started first.
But to answer the question... priorities are mapped to the underlying priorities in the OS threading system. On some systems, the default priority is not enough. For example, Windows will allow a low priority thread to run over a high priority one, in order to avoid thread starvation. On other systems, certain adjacent priority levels are the same, just because there are less priority levels to map to.
So, think of priorities as a hint. The OS will try to honor it, and in most cases, the higher priority thread will get more and longer timeslices. But there is no guarantee that a high priority thread will finish first (or start first).