protected int executeCommand(final String[] commands, final String username, final String password) {
        if (commands == null || commands.length == 0) {
            throw new CommandExecutionException("command is empty.");
        }

        if (logger.isInfoEnabled()) {
            logger.info("Command: {}", String.join(" ", commands));
        }

        final String[] cmds = stream(commands).get(stream -> stream.map(s -> {

    }
  }

  private static final class Listener {
    final Runnable command;
    final Executor executor;

    Listener(Runnable command, Executor executor) {
      this.command = checkNotNull(command);
      this.executor = checkNotNull(executor);
    }

    void execute() {
      try {
        executor.execute(command);
      } catch (RuntimeException e) {
        log.log(
            Level.SEVERE,

    @GuardedBy("lock")
    private int runningTasks = 0;

    @GuardedBy("lock")
    private boolean shutdown = false;

    @Override
    public void execute(Runnable command) {
      startTask();
      try {
        command.run();
      } finally {
        endTask();
      }
    }

    @Override
    public boolean isShutdown() {
      synchronized (lock) {
        return shutdown;

      new ScheduledThreadPoolExecutor(10) {
        @Override
        public ScheduledFuture<?> scheduleWithFixedDelay(
            Runnable command, long initialDelay, long delay, TimeUnit unit) {
          return future = super.scheduleWithFixedDelay(command, initialDelay, delay, unit);
        }
      };

  public void testServiceStartStop() throws Exception {
    NullService service = new NullService();

      new ScheduledThreadPoolExecutor(10) {
        @Override
        public ScheduledFuture<?> scheduleWithFixedDelay(
            Runnable command, long initialDelay, long delay, TimeUnit unit) {
          return future = super.scheduleWithFixedDelay(command, initialDelay, delay, unit);
        }
      };

  public void testServiceStartStop() throws Exception {
    NullService service = new NullService();

    }

    @Override
    public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
      return NeverScheduledFuture.create();
    }

    @Override
    public ListenableScheduledFuture<?> scheduleAtFixedRate(
        Runnable command, long initialDelay, long period, TimeUnit unit) {
      return NeverScheduledFuture.create();
    }

    @Override

    }

    @Override
    public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
      return NeverScheduledFuture.create();
    }

    @Override
    public ListenableScheduledFuture<?> scheduleAtFixedRate(
        Runnable command, long initialDelay, long period, TimeUnit unit) {
      return NeverScheduledFuture.create();
    }

    @Override

        final String commandTimeoutStr = fessConfig.getSystemProperty("thumbnail.command.timeout");
        if (commandTimeoutStr != null) {
            commandTimeout = Long.valueOf(commandTimeoutStr);
        }
        final String commandDestroyTimeoutStr = fessConfig.getSystemProperty("thumbnail.command.destroy.timeout");
        if (commandDestroyTimeoutStr != null) {

import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import static java.util.regex.Pattern.quote;

/**
 * NOTICE: this class is invoked via java command line, so we must NOT DEPEND ON ANY 3RD-PARTY LIBRARIES except JDK 11.
 *
 * Usage: java build-logic/cleanup/src/main/java/gradlebuild/cleanup/services/KillLeakingJavaProcesses.java
 */
public class KillLeakingJavaProcesses {

        final JobProcess jobProcess = runningProcessMap.get(sessionId);
        if (jobProcess == null) {
            throw new JobNotFoundException("Job for " + sessionId + " is not found.");
        }
        try {
            final OutputStream out = jobProcess.getProcess().getOutputStream();
            IOUtils.write(command + "\n", out, Constants.CHARSET_UTF_8);