}

    // Test appendException method with simple exception
    @Test
    public void test_appendException_simpleException() {
        StringBuilder buf = new StringBuilder();
        Exception exception = new RuntimeException("Test error message");

        monitorTarget.appendException(buf, exception);
        assertTrue(buf.toString().startsWith("\"exception\":\""));

                break;
            case "appendException":
                appendExceptionMethod = method;
                break;
            }
        }

        assertNotNull(appendMethod, "Should inherit append method");
        assertNotNull(appendTimestampMethod, "Should inherit appendTimestamp method");
        assertNotNull(appendExceptionMethod, "Should inherit appendException method");
    }

     *
     * @param buf the string buffer to append to
     * @param exception the exception to append
     * @return the updated buffer
     */
    protected StringBuilder appendException(final StringBuilder buf, final Exception exception) {
        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
                PrintWriter writer = new PrintWriter(baos, false, Constants.CHARSET_UTF_8)) {

                return tempBuf.toString();
            }).collect(Collectors.joining(","));
            buf.append(hotThreads).append(',');
        } catch (final Exception e) {
            appendException(buf, e).append(',');
        }

        appendTimestamp(buf);
        buf.append('}');

        if (logger.isInfoEnabled()) {
            logger.info(buf.toString());
        }
    }

            try (OutputStream out = builder.getOutputStream()) {
                stats = ((ByteArrayOutputStream) out).toString(Constants.UTF_8);
            }
        } catch (final Exception e) {
            appendException(buf, e).append(',');
        }
        buf.append("\"search_engine\":").append(stats).append(',');
    }