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);

        assertEquals(2, callbackResults.size());
        assertEquals("integration test", callbackResults.get(0));
        assertEquals("second line", callbackResults.get(1));

        String output = thread.getOutput();
        assertTrue(output.contains("integration test"));
        assertTrue(output.contains("second line"));
    }

    public void test_defaultBufferSizeConstant() throws IOException {

        return String.join("\n", inputs);
    }

    /**
     * Returns the output character sequence that inputs are mapped to.
     *
     * @return the output sequence
     */
    public String getOutput() {
        return output;
    }

    /**
     * Checks whether this mapping item has pending updates.
     *
     * @return true if both newInputs and newOutput are not null, indicating pending updates

    }

    @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));
        });

     */
    public String getInput() {
        return input;
    }

    /**
     * Gets the original output stem.
     *
     * @return The original output stem.
     */
    public String getOutput() {
        return output;
    }

    /**
     * Checks if the item has been updated.
     *
     * @return true if the item has been updated, false otherwise.
     */

            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() {