Using a thread to capture process output

Question

I am using a thread to capture stream output from a process, and then outputting that stream to the eclipse console. The question I have is when to terminate the thread that

Answer 1

You need to process reading the output in a separate thread, theres an example here

Answer 2

You will need to have two threads. One to handle the I/O and another to wait for process completion (Process.waitFor()) and set a flag telling the I/O thread to quit when it exhausts the data.

Answer 3

You can use VerboseProcess from jcabi-log (I'm a developer):

String name = new VerboseProcess(
  new ProcessBuilder("executable with output")
).stdout();

The only dependency you need:

<dependency>
  <groupId>com.jcabi</groupId>
  <artifactId>jcabi-log</artifactId>
  <version>0.7.5</version>
</dependency>

Answer 4

You need to use Process.waitFor() to wait for process completion.

Additionally, you need to consume stdout and stderr concurrently in order to avoid blocking and a possible process hang. Consequently you need two threads to read these streams, and to continue reading whilst the streams are available.

See this Javaworld article for more info and a StreamGobbler implementation to consume the stdout/err.