Chapter 1. Installing the JBoss Communications Platform

You can install the JBoss Communications Platform by downloading the binary distribution.

Before installing the JBoss Communications Platform, you should ensure that you have installed a suitable Java Development Kit or Java Runtime Environment.

1.1. Java Development Kit: Installing, Configuring and Running

The JBoss Communications Platform is written in Java; therefore, before running any JBCP server, you must have a working Java Runtime Environment (JRE) or Java Development Kit (JDK) installed on your system. In addition, the JRE or JDK you are using to run JBCP must be version 5 or higher^[1].

Should I Install the JRE or JDK?

Although you can run JBCP servers using the Java Runtime Environment, we assume that most users are developers interested in developing Java-based, JBCP-driven solutions. Therefore, in this guide we take the tact of showing how to install the full Java Development Kit.

Should I Install the 32-Bit or the 64-Bit JDK, and Does It Matter?

Briefly stated: if you are running on a 64-Bit Linux or Windows platform, you should consider installing and running the 64-bit JDK over the 32-bit one. Here are some heuristics for determining whether you would rather run the 64-bit Java Virtual Machine (JVM) over its 32-bit cousin for your application:

Wider datapath: the pipe between RAM and CPU is doubled, which improves the performance of memory-bound applications when using a 64-bit JVM.
64-bit memory addressing gives virtually unlimited (1 exabyte) heap allocation. However large heaps affect garbage collection.
Applications that run with more than 1.5 GB of RAM (including free space for garbage collection optimization) should utilize the 64-bit JVM.
Applications that run on a 32-bit JVM and do not require more than minimal heap sizes will gain nothing from a 64-bit JVM. Barring memory issues, 64-bit hardware with the same relative clock speed and architecture is not likely to run Java applications faster than their 32-bit cousin.

Note that the following instructions detail how to download and install the 32-bit JDK, although the steps are nearly identical for installing the 64-bit version.

Downloading

You can download the Sun JDK 5.0 (Java 2 Development Kit) from Sun's website: http://java.sun.com/javase/downloads/index_jdk5.jsp. Click on the Download link next to "JDK 5.0 Update <x>" (where <x> is the latest minor version release number). On the next page, select your language and platform (both architecture—whether 32- or 64-bit—and operating system), read and agree to the Java Development Kit 5.0 License Agreement, and proceed to the download page.

The Sun website will present two download alternatives to you: one is an RPM inside a self-extracting file (for example, jdk-1_5_0_16-linux-i586-rpm.bin), and the other is merely a self-extracting file (e.g. jdk-1_5_0_16-linux-i586.bin). If you are installing the JDK on Red Hat Enterprise Linux, Fedora, or another RPM-based Linux system, we suggest that you download the self-extracting file containing the RPM package, which will set up and use the SysV service scripts in addition to installing the JDK. We also suggest installing the self-extracting RPM file if you will be running JBCP in a production environment.

Installing

The following procedures detail how to install the Java Development Kit on both Linux and Windows.

Procedure 1.1. Installing the JDK on Linux

Regardless of which file you downloaded, you can install it on Linux by simply making sure the file is executable and then running it:

~]$ chmod +x "jdk-1_5_0_<minor_version>-linux-<architecture>-rpm.bin"
~]$ ./"jdk-1_5_0_<minor_version>-linux-<architecture>-rpm.bin"

You Installed Using the Non-RPM Installer, but Want the SysV Service Scripts

If you download the non-RPM self-extracting file (and installed it), and you are running on an RPM-based system, you can still set up the SysV service scripts by downloading and installing one of the -compat packages from the JPackage project. Remember to download the -compat package which corresponds correctly to the minor release number of the JDK you installed. The compat packages are available from ftp://jpackage.hmdc.harvard.edu/JPackage/1.7/generic/RPMS.non-free/.

Important

You do not need to install a -compat package in addition to the JDK if you installed the self-extracting RPM file! The -compat package merely performs the same SysV service script set up that the RPM version of the JDK installer does.

Procedure 1.2. Installing the JDK on Windows

Using Explorer, simply double-click the downloaded self-extracting installer and follow the instructions to install the JDK.

Configuring

Configuring your system for the JDK consists in two tasks: setting the JAVA_HOME environment variable, and ensuring that the system is using the proper JDK (or JRE) using the alternatives command. Setting JAVA_HOME usually overrides the values for java, javac and java_sdk_1.5.0 in alternatives, but we will set them all just to be safe and consistent.

Setting the JAVA_HOME Environment Variable on Generic Linux

After installing the JDK, you must ensure that the JAVA_HOME environment variable exists and points to the location of your JDK installation.

Setting the `JAVA_HOME` Environment Variable on Linux

You can determine whether JAVA_HOME is set on your system by echoing it on the command line:

~]$ echo $JAVA_HOME

If JAVA_HOME is not set already, then you must set its value to the location of the JDK installation on your system. You can do this by adding two lines to your personal ~/.bashrc configuration file. Open ~/.bashrc (or create it if it doesn't exist) and add a line similar to the following one anywhere inside the file:

export JAVA_HOME="/usr/lib/jvm/jdk1.5.0_<version>"

You should also set this environment variable for any other users who will be running JBCP (any environment variables exported from ~/.bashrc files are local to that user).

Setting java, javac and java_sdk_1.5.0 Using the alternatives command

Selecting the Correct System JVM on Linux using `alternatives`

On systems with the alternatives command, including Red Hat Enterprise Linux and Fedora, you can easily choose which JDK (or JRE) installation you wish to use, as well as which java and javac executables should be run when called.

As the root user, call /usr/sbin/alternatives with the --config java option to select between JDKs and JREs installed on your system:

root@localhost ~]$ /usr/sbin/alternatives --config java

There are 3 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
   1           /usr/lib/jvm/jre-1.5.0-gcj/bin/java
   2           /usr/lib/jvm/jre-1.6.0-sun/bin/java
*+ 3         /usr/lib/jvm/jre-1.5.0-sun/bin/java


Enter to keep the current selection[+], or type selection number:

In our case, we want to use the Sun JDK, version 5, that we downloaded and installed, to run the java executable. In the alternatives information printout above, a plus (+) next to a number indicates the one currently being used. As per alternatives' instructions, pressing Enter will simply keep the current JVM, or you can enter the number corresponding to the JVM you would prefer to use.

Repeat the procedure above for the javac command and the java_sdk_1.5.0 environment variable, as the root user:

~]$ /usr/sbin/alternatives --config javac

~]$ /usr/sbin/alternatives --config java_sdk_1.5.0

Setting the JAVA_HOME Environment Variable on Windows

For information on how to set environment variables in Windows, refer to http://support.microsoft.com/kb/931715.

Testing

Finally, to make sure that you are using the correct JDK or Java version (5 or higher), and that the java executable is in your PATH, run the java -version command in the terminal from your home directory:

~]$ java -version
java version "1.5.0_16"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_16-b03)
Java HotSpot(TM) Client VM (build 1.5.0_16-b03, mixed mode, sharing)

Uninstalling

There is usually no reason (other than space concerns) to remove a particular JDK from your system, given that you can switch between JDKs and JREs easily using alternatives, and/or by setting JAVA_HOME.

Uninstalling the JDK on Linux

On RPM-based systems, you can uninstall the JDK using the yum remove <jdk_rpm_name> command.

Uninstalling the JDK on Windows

On Windows systems, check the JDK entry in the Start menu for an uninstall command, or use Add/Remove Programs.

^[1] At this point in time, it is possible to run most JBCP servers, such as the JAIN SLEE Server, using a Java 6 JRE or JDK. Be aware, however, that presently the XML Document Management Server does not run on Java 6. We suggest checking the Mobicents web site, forums or discussion pages if you need to inquire about the status of running the XML Document Management Server with Java 6.