assertTrue("Should have line4", thread.contains("line4"));
        assertTrue("Should have line5", thread.contains("line5"));
    }

    public void test_emptyInputStream() throws IOException, InterruptedException {
        Process mockProcess = createMockProcess("");
        JobProcess jobProcess = new JobProcess(mockProcess);

        InputStreamThread thread = jobProcess.getInputStreamThread();

        thread.join(1000);

        assertEquals("All lines should be processed", 5000, receivedLines.size());
        assertEquals("First line", "Line number 0", receivedLines.get(0));
        assertEquals("Last line", "Line number 4999", receivedLines.get(4999));
    }

    public void test_run_concurrentAccess() throws InterruptedException {
        String input = "concurrent1\nconcurrent2\nconcurrent3";

        String[] inputs = { "input" };
        CharMappingItem item = new CharMappingItem(1L, inputs, "output");

        // Test newline replacement in setNewOutput
        item.setNewOutput("line1\nline2\nline3");
        assertEquals("line1 line2 line3", item.getNewOutput());
    }

    public void test_setNewOutput_withNull() {
        String[] inputs = { "input" };
        CharMappingItem item = new CharMappingItem(1L, inputs, "output");

 * <p>Several methods in this class, such as {@link #readLines()}, break the contents of the source
 * into lines. Like {@link BufferedReader}, these methods break lines on any of {@code \n}, {@code
 * \r} or {@code \r\n}, do not include the line separator in each line and do not consider there to
 * be an empty line at the end if the contents are terminated with a line separator.
 *

 * <p>Several methods in this class, such as {@link #readLines()}, break the contents of the source
 * into lines. Like {@link BufferedReader}, these methods break lines on any of {@code \n}, {@code
 * \r} or {@code \r\n}, do not include the line separator in each line and do not consider there to
 * be an empty line at the end if the contents are terminated with a line separator.
 *

            // Verify content structure
            boolean hasThreadLine = lines.stream().anyMatch(line -> line.startsWith("Thread:"));
            boolean hasStackTraceLine = lines.stream().anyMatch(line -> line.startsWith("\tat "));

            assertTrue("Should contain thread information", hasThreadLine);
            assertTrue("Should contain stack trace information", hasStackTraceLine);

    writeLines(lines, System.getProperty("line.separator"));
  }

  /**
   * Writes the given lines of text to this sink with each line (including the last) terminated with
   * the given line separator.
   *
   * @throws IOException if an I/O error occurs while writing to this sink
   */
  public void writeLines(Iterable<? extends CharSequence> lines, String lineSeparator)

   * @return a mutable {@link List} containing all the lines
   * @throws IOException if an I/O error occurs
   */
  public static List<String> readLines(Readable r) throws IOException {
    List<String> result = new ArrayList<>();
    LineReader lineReader = new LineReader(r);
    String line;
    while ((line = lineReader.readLine()) != null) {
      result.add(line);
    }
    return result;
  }

  /**

  }

  /**
   * Streams lines from a URL, stopping when our callback returns false, or we have read all of the
   * lines.
   *
   * @param url the URL to read from
   * @param charset the charset used to decode the input stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @param callback the LineProcessor to use to handle the lines
   * @return the output of processing the lines

  private fun readJournalLine(line: String) {
    val firstSpace = line.indexOf(' ')
    if (firstSpace == -1) throw IOException("unexpected journal line: $line")

    val keyBegin = firstSpace + 1
    val secondSpace = line.indexOf(' ', keyBegin)
    val key: String
    if (secondSpace == -1) {
      key = line.substring(keyBegin)
      if (firstSpace == REMOVE.length && line.startsWith(REMOVE)) {