jdk 1.4, 1.5, 1.6 compiled code differences

Question

I am using a web application were the java code is compiled using jdk 1.4 and i use weblogic 8.1 as my app server which also use jdk 1.4, but there are few finger countable class files compiled using jdk 1.5. Its something like a mix of class files together compiled using jdk 1.4 & 1.5. Now when i try to access the part of application which requires the class files compiled with 1.5 jdk to be executed in order. It will throw ClassDefnNotFound exception.

Any suggesstions.?. I also would require an explaination on the differences between class files compiled using jdk 1.4 and jdk 1.5, if there are any .

Thanks in advance

Answer 1

Looks like you need retroweaver to back-convert your newer code, if you are really using newer features. If you are not, set -target to 1.4 when compiling everything.