JakartaJEEWebDevelopment

Jakarta JEE8 Enterprise Web Development

View on GitHub

Debugging the JEE 8 Web Hello World Servlet module

JEE 8 Hello World Debug Start Branch

1. In Eclipse select Window -> Preferences -> Server -> Runtime Environments -> Select Tomcat 9 and Edit

Ensure that your Tomcat 9 server is set up correctly

2. Now add in-line java code and a debug point to the JSP page

	<%@ page contentType="text/html;charset=UTF-8" language="java" %>
	
	<html>
	
	<head>
	
	<title>Hello, World Application Index File</title>
	
	</head>
	
	<body>
	
	<a href="hello-world">Present the Hello World Input Form...</a><br>
	
	Java runtime version: <%= System.getProperty("java.version") %>
	
	</body>
	
	</html>
Run the Web App in Debug mode
This will stop at the JSP line to debug and open the Eclipse Debug Perspective where you can track the stack

4. Repeat the process with the debug point in the servlet

This will stop at the servlet line to debug and open the Eclipse Debug Perspective where you can track the stack

5. Add basic logging to the JEE 8 Web App

Apache Log4J 2
Add Maven Dependencies
<dependency>
	<groupId>org.apache.logging.log4j</groupId>
	<artifactId>log4j-api</artifactId>
	<version>2.19.0</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.19.0</version>
</dependency>
Add log4j.properties
appenders=xyz
appender.xyz.type=Console
appender.xyz.name=myOutput
appender.xyz.layout.type=PatternLayout
appender.xyz.layout.pattern=[%d{yy-MMM-dd HH:mm:ss:SSS}] [%p] [%c{1}:%L] - %m%n
rootLogger.level=debug
rootLogger.appenderRefs=abc
rootLogger.appenderRef.abc.ref=myOutput
Add debugging code to the Servlet
private static Logger LOGGER = LogManager.getLogger(HelloWorldServlet.class);

LOGGER.info("Servlet " + this.getServletName() + " has started.");

LOGGER.info("Servlet " + this.getServletName() + " has stopped.");
This will allow you to log status and errors

JEE 8 Hello World Servlet Finish Branch