Setting up a Java+Maven on RHEL/Fedora

Java Development on RHEL

(This post is very very boring)

First you need the JDK !

I never understood the config --alternatives command in linux... I guess its really simple. It just configures what symlinks should point to when more than one program is capable of performing a certain function on your machine. 

But, since I just got my RedHat laptop, I had to hack it up to use JDK 64.  Rather than 32 bit java, and I was afraid to "uninstall" 32 bit java, because uninstalling the stock, standard, issued Java seems to have strange consequences sometimes...

So I went about it the "configure --alternatives" route: 

To update java (RHEL): 

jvyas> yum install java-1.6.0-sun-devel.x86_64

jvyas> su
Then, as root: 

root> alternatives --config java

There are 2 programs which provide 'java'.

Selection    Command
-----------------------------------------------
*  1           /usr/lib/jvm/jre-1.6.0-sun.x86_64/bin/java

+ 2           /usr/lib/jvm/jre-1.6.0-sun/bin/java

Fedora?

             To install java on Fedora  (openjdk)
             jvyas> sudo yum list *java* | grep open | grep devel #<-- sanity check to see what JDKs are
             available.
             Hopefully, you should see something like "java-1.6.0-openjdk-devel.x86_64".
             jvyas> sudo yum install java-1.6.0-openjdk-devel.x86_64


And next, you simply hit (1) to tell your machine to use java.

And then if you run it a second time, you can see that you are now using the up to date java, with the other one still intact:

root> alternatives --config java

There are 2 programs which provide 'java'.



  Selection    Command
-----------------------------------------------
*+ 1           /usr/lib/jvm/jre-1.6.0-sun.x86_64/bin/java
   2           /usr/lib/jvm/jre-1.6.0-sun/bin/java

And then theres finally the grand finale:

[root@jvyas usr]# java -version
java version "1.6.0_37"
Java(TM) SE Runtime Environment (build 1.6.0_37-b06)
Java HotSpot(TM) 64-Bit Server VM (build 20.12-b01, mixed mode)

Yay for 64 bit JDK :)


SETTING UP MAVEN

Now you (probably) need Maven .. (no, you cant just say "yum install mvn")? So.. here's how you do it.

#The OLD maven (not sure how often this is updated)

wget -O /etc/yum.repos.d/jpackage50.repo http://www.jpackage.org/jpackage50.repo

yum install maven2

The up to date way

wget -O /opt/apache-maven-3-bin.tar.gz http://apache.petsads.us/maven/maven-3/3.0.5/binaries/apache-maven-3.0.5-bin.tar.gz maven-2.2.1-bin.tar.gz 

ln -s /opt/apache-maven-3.0.5/bin/mvn /usr/bin/mvn

Now you should be able to run "mvn --version" from anywhere after you open a new terminal, to confirm that your mvn was installed properly.

Yippee ... mvn3 + java 6+ = dev productivity.