thread.start();

        Thread.sleep(50);

        String output1 = thread.getOutput();
        boolean contains1 = thread.contains("concurrent1");

        thread.join(1000);

        String output2 = thread.getOutput();
        boolean contains2 = thread.contains("concurrent1");

        assertNotNull(output1);
        assertNotNull(output2);

    }

    @ParametricNullness
    abstract T getOutput(int entry);

    @Override
    @ParametricNullness
    public T next() {
      checkForConcurrentModification();
      if (!hasNext()) {
        throw new NoSuchElementException();
      }
      indexToRemove = currentIndex;
      T result = getOutput(currentIndex);
      currentIndex = getSuccessor(currentIndex);

        assertEquals("c", item1.getOutput());

        OptionalEntity<CharMappingItem> result2 = charMappingFile.get(2L);
        assertTrue(result2.isPresent());
        CharMappingItem item2 = result2.get();
        assertEquals(2L, item2.getId());
        assertArrayEquals(new String[] { "d", "e" }, item2.getInputs());
        assertEquals("f", item2.getOutput());

        charMappingService.getCharMappingItem(form.dictId, form.id).ifPresent(entity -> {
            form.inputs = entity.getInputsValue();
            form.output = entity.getOutput();
        }).orElse(() -> {
            throwValidationError(messages -> messages.addErrorsCrudCouldNotFindCrudTable(GLOBAL, form.getDisplayId()),
                    () -> asListHtml(form.dictId));
        });

            final int exitValue = currentProcess.exitValue();

            if (logger.isInfoEnabled()) {
                logger.info("SuggestCreator: Exit Code={} - Process Output:\n{}", exitValue, it.getOutput());
            }
            if (exitValue != 0) {
                final StringBuilder out = new StringBuilder();
                if (processTimeout) {

            final int exitValue = currentProcess.exitValue();

            if (logger.isInfoEnabled()) {
                logger.info("ThumbnailGenerator: Exit Code={} - Process Output:\n{}", exitValue, it.getOutput());
            }
            if (exitValue != 0) {
                final StringBuilder out = new StringBuilder();
                if (processTimeout) {

        assertEquals("line1 line2", item.getOutput());
    }

    public void test_constructor_withNullOutput() {
        // Test with null output
        String[] inputs = { "input" };
        CharMappingItem item = new CharMappingItem(1L, inputs, null);

        assertNull(item.getOutput());
    }

    public void test_constructor_withUnsortedInputs() {

    }

    @ParametricNullness
    abstract T getOutput(int entry);

    @Override
    @ParametricNullness
    public T next() {
      checkForConcurrentModification();
      if (!hasNext()) {
        throw new NoSuchElementException();
      }
      indexToRemove = currentIndex;
      T result = getOutput(currentIndex);
      currentIndex = getSuccessor(currentIndex);

            final int exitValue = currentProcess.exitValue();

            if (logger.isInfoEnabled()) {
                logger.info("Crawler: Exit Code={} - Process Output:\n{}", exitValue, it.getOutput());
            }
            if (exitValue != 0) {
                final StringBuilder out = new StringBuilder();
                if (processTimeout) {

            }

            final int exitValue = currentProcess.exitValue();

            if (logger.isInfoEnabled()) {
                logger.info("Exit Code: {} - Process Output:\n{}", exitValue, it.getOutput());
            }
            if (exitValue == 143 && mt.isTeminated()) {
                throw new CommandExecutionException("The command execution is timeout: " + String.join(" ", commands));
            }