ServletContext.log() not logging - gwt

Question

Log output of my RemoteServiceServlet (GWT) is not shown in Logfiles or Stdout when using getServletContext().log("anything");
For dependency injection I use Google Guice. For my own log output I use slf4j-jdk14. I tried this in Tomcat 6 as well as in Jetty (GWT devmode).
To make it clear, my Servlet:
#Singleton
public class MyServiceServlet extends RemoteServiceServlet implements MyService {
private static final Logger log = LoggerFactory.getLogger(MyServiceServlet.class);
private final ADependency dep;
#Inject
public MyServiceServlet(ADependency dep) {
getServletContext().log("THIS IS NOT SHOWN IN MY LOGS");
log.error("THIS IS SHOWN IN MY LOGS");
this.dep = dep;
}
}
So, where can I find the missing log output or where can I configure the ServletContext-Log?

Answer 1

The ServletContext.log method behavior is container specific. The method I have used to make it consistent is to wrap the ServletConfig passed in through init() in order to create a wrapped ServletContext which uses our own provided logger (Slf4j in this case).
public class Slf4jServletConfigWrapper implements ServletConfig {
private final ServletConfig config;
private final Logger log;
public Slf4jServletConfigWrapper(Logger log, ServletConfig config) {
this.log = log;
this.config = config;
}
public ServletContext getServletContext() {
return new ServletContext() {
public void log(String message, Throwable throwable) {
log.info(message, throwable);
}
public void log(Exception exception, String msg) {
log.info(msg, exception);
}
public void log(String msg) {
log.info(msg);
}
...
Full Slf4jServletConfigWrapper.java code
In your Servlet override the init() method to use the ServletConfig wrapper
public void init(final ServletConfig config) throws ServletException {
super.init(new Slf4jServletConfigWrapper(log, config));
}