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UnsupportedClassVersionError

rahulJ james
Ranch Hand

Joined: Oct 03, 2008
Posts: 123
I am using apache-tomcat 5.5 with the compatibility package in order to use that with JRE 1.4.1_17. We built the application 3 years back and I believe I was using the same configuration. When I tried to bring this application back in my system with the above configuration. I got the below mentioned error. Can anyone advise.



Because of this I am not able to bring this application up. Is there any issue with the version of JRE I use or I am not sure..

I tried installing JRE 5.0 but it ended up with a different error saying that 'JDBC driver is not found'

Can anyone advise
Tim Holloway
Saloon Keeper

Joined: Jun 25, 2001
Posts: 16019
    
  20

I think that your copy of Tiles was compiled under Java 5 and you're attempting to run it in a java 1.4 environment.

Java 1.4 is long since past end-of-life and even Java 5 should be receeding in the rear-view mirror at this point. For that matter, it wouldn't be a bad idea to move to Tomcat 6, since Tomcat 7 is probably going to go into production between too much longer.

Getting too far behind the curve doesn't save anything. While it's true that Java - unlike certain other platforms I could mention - doesn't force you into panic upgrades, you're not going to find too much support once things get really ancient, and you're also putting yourself at risk because older releases have security issues that newer releases have repaired. Plus Tomcat continues to get better performance with each new release.

It's a lot easier to fix a "jdbc driver not fond" problem than a class version issue, so that should be an indication right there as to the best approach. You just need to find a suitable JDBC driver and put it in the proper Tomcat library directory. I think it's server/lib, but I haven't run Tomcat 5 in probably 4 years now so I no longer remember. Tomcat6 doesn't require 3 separate library directories like earlier Tomcats did.


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rahulJ james
Ranch Hand

Joined: Oct 03, 2008
Posts: 123
As per your advise, I upgraded the JRe version to 1.5 and using tomcat 6. I am getting a different kind of error where it says as mentioned below, I found the same question in another place where someone has addressed saying that this can be a firewall issue. Not sure what I should do here..



The above error is in my local server. Similarly I get something like below in my unix server too which was working all these years.



Please help
Tim Holloway
Saloon Keeper

Joined: Jun 25, 2001
Posts: 16019
    
  20

It probably is a firewall issue. Either that or your port number in the JDBC URL is incorrect. DB2 doesn't seem to be as fixated on using a standardized port number as most jdbc-supporting DBMS's (such as PostgreSQL's port 5432), so you need to make sure you and your DBA are both set up for the same port number.
 
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subject: UnsupportedClassVersionError