[tip of the day] Execute a Process Without a Hang

Вы частенько висли на exec()?

You may have noticed that running a process from Java using Runtime.exec() sometimes hangs the process. This is true especially in those cases where the process runs in the background. The output stream of the process soon gets filled and when no more data can be written on it, the process hangs.

The following code flushes the process' output stream:

	Process p = Runtime.getRuntime().exec(cmd);
	java.io.InputStream is = p.getInputStream();
	input = new java.io.DataInputStream(new java.io.BufferedInputStream(is));
	line = input.readLine(); // Read one line at a time
	while (line != null) // Iterate for all lines in the input stream
	{
		line = input.readLine();
	}

You can also modify this code to flush the process' error stream—if you expect more data in the error stream.