javaBootcampNoEclipse/docs/javaBootcampNoEclipse.org

Dude! Where's my Eclipse!?

• Dude! Where's my Eclipse
  • Pre-requisites
  • Setting up
  • Lesson 1 – compile the code.
    • Starting point
    • Goal
    • Steps
  • Lesson 2 – build the jar file
    • Starting point
    • Goal
    • Steps
  • Lesson 3 – build the war file
    • Starting point
    • Goal
    • Steps
  • Lesson 4 – deploy and test
    • Starting point
    • Goal
    • Steps
  • Lesson 5 – Add new functionality
    • Starting point
    • Goal
    • Steps
  • Fin

Dude! Where's my Eclipse

Pre-requisites

You will need a linux server with the following installed:

tomcat

This demo was prepare with tomcat-8.

tomcat manager

Used for deploying your built application

A web browser

For accessing the tomcat manager

git

To access the project

a text editor

To fix any bugs you find (Don't use eclipse, or any other "IDE", because that's the whole point.)

java 8 JDK

To build code

If you develop on one machine and deploy to the other, then tomcat and tomcat manager are to be on the system you're deploying to, and the rest where you're developing.

If your development environment is not on the same server as the tomcat instance, you'll need a copy of the file tomcat8-servlet-api.jar on the same system as your java code.

Setting up

0. All commands assume a Linux environment. ${HOME} refers to the home directory of the user, and ${DEV_HOME} refers to where the git repository has been cloned to.

1. Get the code

   git clone https://gitlab.com/eibhear/javaBootcampNoEclipse.git
   

   The repository is now in ${DEV_HOME}. Set that as an environment variable and change into it:

   export DEV_HOME=$(pwd)/javaBootcampNoEclipse
   cd ${DEV_HOME}
   

2. Make sure you're at the starting point:

   git checkout lesson-1
   

Lesson 1 – compile the code.

Starting point

A clean git working area

Goal

Java files compiled into class files

Steps

0. Confirm you can access the java compiler:

   javac -version
   

   If this doesn't result in a message that looks something like javac 1.8.0_141, you'll need to find where javac is installed and place it on your ${PATH}.

1. Change to where the code is:

   cd ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse
   

2. Compile the files:

   javac *.java
   

3. Check the errors. If you see the message

   error: package javax.servlet does not exist
   

   then look at your CLASSPATH setting, as dependent libraries are missing.

4. Fix your CLASSPATH and compile the java files:

   export CLASSPATH=/usr/share/java/tomcat8-servlet-api.jar:${CLASSPATH}
   javac *.java
   

5. If successful, you will have the following additional files under ${DEV_HOME}/source/java/:

   org/gibiris/javaBootcampNoEclipse/MyHelloWorldBean.class
   org/gibiris/javaBootcampNoEclipse/MyHelloWorldServlet.class
   

   If this is the case, move on to lesson 2:

   git checkout lesson-2
   

Lesson 2 – build the jar file

Starting point

A clean git working area with two additional class files in ${DEV_HOME}/source/java/:

org/gibiris/javaBootcampNoEclipse/MyHelloWorldBean.class
org/gibiris/javaBootcampNoEclipse/MyHelloWorldServlet.class

Goal

Class files archived into a jar file

Steps

1. Decide whether you want to include the source (*.java) files in the jar file.
2. Determine other files to be included in the jar file (e.g. config files, property files, etc.).

3. Change to the top-level of the package in the source:

   cd ${DEV_HOME}/source/java
   

   Create the lib/ directory to take the jar file:

   mkdir -pv ../lib
   

4. If you're not including the source files in the jar:

   jar cvf ../lib/javaBootcampNoEclipse.jar \
       org/gibiris/javaBootcampNoEclipse/*.class
   

5. If you are including the source files in the jar:

   jar cvf ../lib/javaBootcampNoEclipse.jar org
   

6. If successful, you will now have a new file:

   ${DEV_HOME}/source/lib/javaBootcampNoEclipse.jar
   

   If this is the case, move on to lesson 3:

   git checkout lesson-3
   

Lesson 3 – build the war file

Starting point

A clean git working area with two additional class files in ${DEV_HOME}/source/java/:

org/gibiris/javaBootcampNoEclipse/MyHelloWorldBean.class
org/gibiris/javaBootcampNoEclipse/MyHelloWorldServlet.class

and one additional jar file in ${DEV_HOME}/source/lib/:

javaBootcampNoEclipse.jar

Goal

A deployable war file

Steps

0. Review the following:

   • http://tomcat.apache.org/tomcat-8.0-doc/appdev/deployment.html to understand the structure of the file web.xml and the war file
   • ${DEV_HOME}/source/res/web.xml to understand how this application is to be used

1. Create an empty directory in ${DEV_HOME} called webapp, then its directory structure, and then change into it:

   mkdir -vp ${DEV_HOME}/webapp
   mkdir -vp ${DEV_HOME}/webapp/WEB-INF/lib
   cd ${DEV_HOME}/webapp
   

2. Copy in the jsps:

   cp -rv ${DEV_HOME}/source/jsps/* ${DEV_HOME}/webapp
   

3. Copy in the jar file:

   cp -rv ${DEV_HOME}/source/lib/javaBootcampNoEclipse.jar \
       ${DEV_HOME}/webapp/WEB-INF/lib
   

4. Copy in the web.xml file:

   cp -rv ${DEV_HOME}/source/res/web.xml \
       ${DEV_HOME}/webapp/WEB-INF
   

5. Create the war file:

   jar cvf ${DEV_HOME}/source/lib/javaBootcampNoEclipse.war *
   

6. If this was successful you will now have a new file:

   ${DEV_HOME}/source/lib/javaBootcampNoEclipse.war
   

7. If this is the case, remove the direcory ${DEV_HOME}/webapp and move on to lesson 4:

   cd ${DEV_HOME}; rm -fr ${DEV_HOME}/webapp
   git checkout lesson-4
   

Lesson 4 – deploy and test

Starting point

1. A clean working area with two additional class files in ${DEV_HOME}/source/java/:

   org/gibiris/javaBootcampNoEclipse/MyHelloWorldBean.class
   org/gibiris/javaBootcampNoEclipse/MyHelloWorldServlet.class
   

   one additional jar file and one additional war file, both in ${DEV_HOME}/source/lib:

   javaBootcampNoEclipse.jar
   javaBootcampNoEclipse.war
   

Goal

A working application

Steps

0. Some pre-steps

   • If this isn't the first time to deploy, be sure to undeploy the previous version of the application.
   • To follow these steps, you'll need your file javaBootcampNoEclipse.war to be accessible locally to your browser.
1. Navigate to http://server:8080/manager (where server is where your tomcat instance is running)
2. Go to the WAR file to deploy section and use the Browse… button to select the war file to deploy (javaBootcampNoEclipse.war).
3. Press the Deploy button. If successful, you'll see your application shown in the list.
4. Go to http://server:8080/javaBootcampNoEclipse to access your app.

5. Test the application. If all is well, clean up your development environment altogether:

   rm -vf ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse/*.class
   rm -vf ${DEV_HOME}/source/lib/javaBootcampNoEclipse.?ar
   rm -vfr ${DEV_HOME}/webapp
   

6. Move on to lesson 5:

   git checkout lesson-5
   

Lesson 5 – Add new functionality

Starting point

A clean working area, brought up to date to include the two new files – Astro/AstroFun.java in ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse and AstroLib-1.1.5ws.jar in ${DEV_HOME}/source/lib – and an update to MyHelloWorldServlet.java in ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse.

Goal

A working, updated application deployed to tomcat.

Steps

0. Pre-steps

   • Make sure your environment is set up as per the previous lessons:

     • DEV_HOME is set to where the git repository is cloned to
     • CLASSPATH contains tomcat8-servlet-api.jar

   • Clean out the working area if there are unnecessary/unwanted files:

     cd ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse; \
         rm -vf *.class; rm -vf Astro/*.class
     rm -vf ${DEV_HOME}/source/lib/javaBootcampNoEclipse.?ar
     rm -vfr ${DEV_HOME}/webapp
     

   • Review the changes that have been applied to the working area

1. Compile the java files (including the new java file) as per Lesson 1.

   Does it compile? If not, why not? Three hints:

   • There was a new sub-package added, org.gibiris.javaBootcampNoEclipse.Astro, which your java compiler needs to be able to find
   • There was a new jar file introduced to the repository
   • There's a bug in the package specification in the new java file. Looking closely at the branches of this git repository, you might even find a fix for it.
2. Build the jar file as per Lesson 2 (except, this time, the lib directory exists already).
3. Build the war file as per Lesson 3.
4. Deploy the updated application as per Lesson 4. You will need to undeploy the previous version first. Does it deploy? Why not? If it deploys, does it work? Why not? (Hint: there was a new jar file introduced to the repository)
5. Fix the new bug, undeploy the bad application and deploy the corrected one.

Fin

Look closely. At last, you get to see an eclipse!

Hint: what's happening[fn:longPast:… or "what happened" if it has gone past] in Grand Island in Nebraska at ~13:00 local time on [2017-08-21 Mon]?