public ProcessStreamReader start() {
    synchronized (this) {
      if (thread == null) {
        thread = new LoggingThread(createThreadName(), this);
        thread.start();
      } else if (thread.isAlive()) {
        throw new IllegalStateException(this + " has already started");
      } else {
        throw new IllegalStateException(this + " was stopped and cannot be restarted");
      }
    }
    return this;
  }
Reads the output stream of a Process.

@since GemFire 7.0
geode-core/src/main/java/org/apache/geode/internal/process/ProcessStreamReader.java