Java - huge speed differences between JRE and JDeveloper

I'm developing a Java program that produces SVG plots. The application itself is called from a Java servlet that is running on a Tomcat server. The JRE installed on the server is the latest - 1_5_0_05. The code accesses a pair of Access database files to get data from. When I run it on the server it runs incredibly slowly. I installed the same JRE version to my PC and it also runs slowly on my machine. The code was developed using Oracle JDeveloper though, when I run it using the JRE that comes with it the speed is drastically better. I did some timing and on my PC the code takes about 1 3/4 minutes to run under JRE 1_5_0_05 but only 8 second to run under the JDeveloper runtime. The version for JDeveloper says it is 1.4.2_03. I think they've modified it to improve database performance since I also have the same version as a JRE on my PC and it runs almost as slow (about 1 minute 15 seconds).

Any ideas on what I can do to improve performance? The JDeveloper runtime doesn't actually get installed normally - everything is in a Zip file which I extract.