public String getUserId() {
        return username;
    }

    /**
     * Returns a string representation of this credential.
     *
     * @return A string representation containing the username in braces
     */
    @Override
    public String toString() {
        return "{" + username + "}";
    }

        sb.append(",").append(appTypeSupplier.supply()).append(",").append(resource.getModuleName());
        final String trace = sb.toString();
        final int columnSize = 200;
        return trace.length() > columnSize ? trace.substring(0, columnSize) : trace;
    }

    public void test_stackTrace() {
        // Test stack trace is properly set
        ResultOffsetExceededException exception = new ResultOffsetExceededException("Stack trace test");

        StackTraceElement[] stackTrace = exception.getStackTrace();
        assertNotNull(stackTrace);
        assertTrue(stackTrace.length > 0);

        // Check that the current test method is in the stack trace
        boolean foundTestMethod = false;

            writer.accept("Thread: " + entry.getKey());
            final StackTraceElement[] trace = entry.getValue();
            for (final StackTraceElement element : trace) {
                writer.accept("\tat " + element);
            }
        }
    }

        if (Constants.NONE.equals(llmType)) {
            if (logger.isTraceEnabled()) {
                logger.trace("[LLM] LLM not available. llmType=none");
            }
            return false;
        }
        if (!isRagChatEnabled()) {
            if (logger.isTraceEnabled()) {
                logger.trace("[LLM] LLM not available. ragChatEnabled=false");
            }
            return false;
        }

        return actionClass;
    }

    /**
     * Overrides fillInStackTrace to return null for performance optimization.
     * This prevents stack trace generation for this exception type.
     *
     * @return null to skip stack trace generation
     */
    @Override
    public synchronized Throwable fillInStackTrace() {
        return null;
    }

        String errorMessage = "Stack trace test error";
        ServletException servletException = new ServletException(errorMessage);

        // Wrap it in ServletRuntimeException
        ServletRuntimeException runtimeException = new ServletRuntimeException(servletException);

        // Verify stack trace is available
        StackTraceElement[] stackTrace = runtimeException.getStackTrace();

    @Test
    public void test_stackTraceForMessageOnlyConstructor() {
        // Test that stack trace is not writable when using message-only constructor
        ThumbnailGenerationException exception = new ThumbnailGenerationException("Test message");

        // The message-only constructor uses super(message, false, false) which disables stack trace
        assertEquals(0, exception.getStackTrace().length);
    }

    @Test

    @Test
    public void test_stackTrace() {
        // Test that stack trace is properly captured
        final JobProcessingException exception = new JobProcessingException("Stack trace test");

        assertNotNull(exception.getStackTrace());
        assertTrue(exception.getStackTrace().length > 0);

        // Verify the top of the stack trace points to this test method

        assertTrue(exception instanceof java.io.Serializable);
    }

    @Test
    public void test_stackTrace() {
        // Test that stack trace is properly preserved
        String message = "GSA error with stack trace";
        Throwable cause = new NullPointerException("NPE occurred");
        GsaConfigException exception = new GsaConfigException(message, cause);