flush printwriter on application close

Question

So I have a printwriter that will occasionally write to a file ("occasionally" here meaning "periodically after a certain number of specified events").

Now if these events happen to be too few, the log file may end up empty when the application is terminated (Ctrl + C).

I could, of course, flush after every println, but that would defeat the purpose of having a non-auto-flush printwriter (which is the only kind that can be created anyway if I want to pass a File as a constructor argument).

Is there a onApplicationKill-thing in Java I could instrument to flush the writer once when the application is terminated? Or something to detect when the current thread is killed?

Have a look [here](http://stackoverflow.com/questions/2975248/java-how-to-handle-a-sigterm)! — ArcticLord, Oct 11 '16 at 10:19

score 3 · Accepted Answer · answered Oct 11 '16 at 10:18

3

You can use a shutdown hook:

Runtime.getRuntime().addShutdownHook(new Thread() {
  public void run() {
      ...
      writer.flush();
  }
});

It should also work if you kill it with Ctrl+C

answered Oct 11 '16 at 10:18

Stefan

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flush printwriter on application close

1 Answers1