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Log4j - Email errors using Gmail

Most of the small projects doesn't have a dedicated person to monitor log file all the times, and its handy to send these errors as email to an email list.


  1. Never miss an error.
  2. Delete Emails which you want to ignore because of invalid inputs or connectivity issues etc.
  3. Proactively identify bugs and fix them.
  4. Email list is handy i.e. multiple person can receive emails.
  5. If you have different modules in your project and different teams work on them, adding a Labels to your log can by handy since most of the Email Servers can Label emails and redirect them to different folders.
  1.    Sending email from code takes few seconds, workaround is the create Logger wrapper which logs in a separate thread.

log4j.rootLogger=ERROR, gmail subject line{MM/dd/yyyy HH:mm:ss}  [%M] %-5p %C - %m%n

Required Jar files

Activation  download from here

Sample Code

public class Log4jGmailDemo {

    public static void main(String[] args) {
        try {
            int z = 4 / 0;
        } catch (RuntimeException re) {
            logger.error("Module-1", re);
    static Logger logger = Logger.getLogger(Log4jGmailDemo.class);

This is only if you are interested using Threads 

public class CustomLogger extends Logger {

    public CustomLogger(String clazz) {

    public void error(Object message) {
        Runnable runnable = new LoggerRunnable(this, message, null);

    public void error(Object message, Throwable throwable) {
        Runnable runnable = new LoggerRunnable(this, message, throwable);

    public static Logger getLogger(Class clazz) {
        return new CustomLogger(clazz.getSimpleName());

class LogExecutor {

    private static LogExecutor executor = new LogExecutor();

    private LogExecutor() {
    private ExecutorService service = Executors.newFixedThreadPool(5);

    public static LogExecutor getInstance() {
        return executor;

    public void execute(Runnable runnable) {

class LoggerRunnable implements Runnable {

    private Logger logger;
    private Object message;
    private Throwable throwable;

    public LoggerRunnable(Logger logger, Object message, Throwable throwable) {
        this.logger = logger;
        this.message = message;
        this.throwable = throwable;

    public void run() {
        logger.error(message, throwable);

Sample Usage

public class Log4jGmailDemo {

    public static void main(String[] args) {
        try {
            int z = 4 / 0;
        } catch (RuntimeException re) {
            logger.error("Module-1", re);
    static Logger logger = CustomLogger.getLogger(Log4jGmailDemo.class);


Steven said…
Nice article. Just to add: you can use AsyncAppender to make non-blocking emailing of logs instead of writing your own.

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