code: def post_fork_child(self, fingerprint, jvm_options, classpath, stdout, stderr):
      
      java = SubprocessExecutor(self._distribution)
  
      subproc = java.spawn(classpath=classpath,
                           main='com.martiansoftware.nailgun.NGServer',
                           jvm_options=jvm_options,
                           args=[':0'],
                           stdin=safe_open('/dev/null', 'r'),
                           stdout=safe_open(self._ng_stdout, 'w'),
                           stderr=safe_open(self._ng_stderr, 'w'),
                           close_fds=True)
  
      self.write_pid(subproc.pid)
docs: Post-fork() child callback for ProcessManager.daemon_spawn().