How do I suppress Jetty 8's default ErrorHandler?

Question

Jetty is helping my application too much. Whenever some unhandled Exception leaks out the top, Jetty takes it upon itself to build a very verbose response and spam it onto my clients

HTTP/1.1 500 com.mongodb.MongoException: No replica set members available in [ { address:'localhost/127.0.0.1:27017', ok:true, ping:0.49878865, isMaster:false, isSecondary:true, setName:dmReplSet, maxBsonObjectSize:16777216, },{ address:'localhost/127.0.0.1:27018', ok:true, ping:0.2565605, isMaster:false, isSecondary:true, setName:dmReplSet, maxBsonObjectSize:16777216, } ] for { "mode" : "primary"}

along with 14K of stacktrace wrapped in a very nice HTML page. The problem is, I don't want the details of the issue leaking out to the clients and, further, this is a JSON Web App accepting and emitting application/json content NOT the HTML Jetty has decided my clients want. I would like to suppress this default error handling having Jetty emit just that standard HTTP 500 response

HTTP/1.1 500 Internal Server Error

and no body at all. How do I get this done? It seems like I should be able to just tell Jetty to "no error page" in etc/jetty.xml or etc/jetty-webdefault.xml or something.

Answer 1

So this seems most easily solved without binding myself to Jetty too much by <error-page> in web.xml

<servlet>
    <servlet-name>ErrorHandler</servlet-name>
    <servlet-class>device.webapp.ErrorHandler</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>ErrorHandler</servlet-name>
    <url-pattern>/ErrorHandler</url-pattern>
</servlet-mapping>

<error-page>
    <exception-type>java.lang.Throwable</exception-type >
    <location>/ErrorHandler</location>
</error-page>

Implementing ErrorHandler like

package device.webapp;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.commons.httpclient.*;
import org.slf4j.*;

/**
 * The ErrorHandler is intended to catch all unhandled Throwables (as configured in the web.xml)
 * before they get out to Jetty's verbose ErrorHandler.
 * 
 */
public class ErrorHandler extends HttpServlet {

    private static final long serialVersionUID = 1L;
    private Logger log = LoggerFactory.getLogger( ErrorHandler.class );

    @Override
    protected void service( HttpServletRequest req, HttpServletResponse resp ) throws ServletException, IOException {
        // Analyze the servlet exception
        Throwable throwable = (Throwable) req.getAttribute( "javax.servlet.error.exception" );
        String message = String.format(
                "Responding 500 - Server Error on URI %s",
                req.getAttribute( "javax.servlet.error.request_uri" ) );
        if ( throwable != null ) {
            log.error( message, throwable );
        } else {
            log.warn( "Throwable should not be null!" );
            log.error( message );
        }

        /*
         * Interestingly enough, you can't resp.sendError( 500, "Server Error" ) without triggering
         * Jetty's DefaultErrorHandler which is the core of the problem we are trying to solve!
         */
        resp.setStatus( HttpStatus.SC_INTERNAL_SERVER_ERROR );
    }
}

It isn't pretty, but it works.