Java

Java is a language and set of libraries developed by Sun Microsystems. DreamHost has Java installed, but you cannot run JavaServlets nor JSP unless you can configure it on a DreamHost PS.

What Version?
[thunderkittens]$ /usr/bin/java -version java version "1.6.0_07" Java(TM) SE Runtime Environment (build 1.6.0_07-b06) Java HotSpot(TM) 64-Bit Server VM (build 10.0-b23, mixed mode)

Do you have a JDK installed? Where is the JDK?
Yes! The JDK is installed in /usr/local/dh/java

You can set your JAVA_HOME by doing the following (if you are using the bash shell) export JAVA_HOME=/usr/local/dh/java

Which java features do you support / not support?
WE SUPPORT the following:
 * Java (in general)
 * Java Applets
 * Java2
 * Java SDK/JRE (Software Devel Kit/Java Runtime Environment)

WE DO NOT SUPPORT:
 * Java Servlets
 * JSP
 * Tomcat/Jakarta (a JSP engine)
 * EJB (Enterprise Java Beans)
 * J2EE
 * Pretty much anything else Java-related.

Do you support Java applets?
Java applets are applications that run on the user's browser, as opposed to CGI programs, which run on the server.

Yes, we do support them.

Do you support Java servlets?
Sadly, no, but if you have a DreamHost PS it is possible.

While certainly a useful technology, Apache JServ has been in maintenance mode for quite some time now (the last release as of this writing was on June 17th, 2000), and as time goes on it will be more and more difficult to integrate it with other technologies we operate on.

We have closely evaluated the most obvious alternative (Jakarta Tomcat), but due to an inherent limitation in the way Tomcat was designed it is not a feasible alternative when used in a shared web hosting environment, even by their own admission. We've also evaluated a number of commercial solutions, but have not found a viable, cost-effective replacement that will work on all of our shared hosting servers.

[http://tomcat.apache.org/tomcat-5.5-doc/virtual-hosting-howto.html What more do you need beyond virtual hosts? ]

[This article was last updated before January 2006. If you have new information, please update this article.]

comment re: technical rationale
In an old, 2005 thread,


 * Java PHP Bridge

DH mgmt had commented,


 * " ... This is excellent information. Thank you! We have looked at tomcat before, but not recently. It sounds like it's worth another look. ..."

I have no idea whether that 'look' was, in fact, taken, and whether a business decision was made to not deploy Tomcat.

Given the aforementioned,


 * " ... due to an inherent limitation in the way Tomcat was designed it is not a feasible alternative when used in a shared web hosting environment, even by their own admission ..."

as well as the note that,


 * "[This article was last updated before January 2006. If you have new information, please update this article.]"

I'll suggest that that may, in fact, be outdated/inaccurate information.

The most obvious issue is that the link, above, references Tomcat 5.5. As of this edit's date, Tomcat's current release version is at 6.0.20. Some time has, indeed, passed.

Next, a quick Google search,


 * Google Search for tomcat+"shared hosting"

suggests that numerous Tomcat, shared-hosting services are currently available. Clearly, someone's got 'it' figured out.

Further, referencing,


 * "Tomcat: The Definitive Guide, Second Edition"

verifies that Tomcat is readily & reliably shareable, via a number of approaches. Highest-performance is, of course, full Tomcat deployment -- i.e., instead of Apache. Admittedly, not a likely option @ DH. But, Tomcat is reliably deployable via Apache mod_proxy -- although this approach cuts ultimate performance by about 50%.

In a downloadable Sample Chapter (.pdf),


 * "Chapter 4: Tomcat Performance Tuning"

the author addresses performance comparisons of various approaches.

Given the apparent technical viability of shared-host, Tomcat deployment, perhaps those among us with interest can, now, communicate said interest to DH and make the business case.

Then again, perhaps there's a more recent technical issue, unique to DH, that'll continue to present a hurdle, unless have a DreamHost PS, install Tomcat and configure the proxy, it may work.

Do you support JSP?
JSP (Java Server Pages) is a format for using Java to dynamically generate web content.

DreamHost does not offer JSP on shared hosting plans.

Do you support Enterprise Java Beans?
Enterprise Java Beans, the server-side component architecture for the J2EE platform, enables rapid and simplified development of distributed, transactional, secure, and portable Java applications.

DreamHost does not support Enterprise Java Beans.

Do you support J2EE?
J2EE (Java 2 Enterprise Edition) is NOT supported by DreamHost.

Do you support the Tomcat/Jakarta JSP engine?
No. DreamHost does not support the Tomcat/Jakarta JSP engine unless you use a DreamHost PS.

Do you support JavaScript?
Of course we do! "Java" and "JavaScript" are two entirely different things.

Java is software that runs on our server.

JavaScript on the other hand, is software that is stored on our server, but runs on your computer in your web browser.

xkahn @ Jun 3 2011: I would point out that JavaScript is slowly becoming a server technology through servers like node.js, and likely not supported by DH (only on PS/DS).

Related articles

 * KB / Web Programming / Do you support....? / Do you support Java? — article from old DreamHost Knowledgebase; content incorporated above
 * Email to Script — example of how to invoke Java code to process an incoming email
 * How a client side script can connect to MySQL - Ex. Java Applet — question with no answer as yet
 * JavaScript