I finally installed j2sdk 1.5.0 and tried to compile my j2ee application using
ant.
Unfortunately ant failed to find the one 1.5.0 class I tried to use
(java.security.Timestamp).
After looking into it a bit (using the verbose switch for ant and javac) I
discovered that ant does not build all the necessary paths. Anyway, that's ok
because I can provide it with them. When I do that I get the following error:

[javac] class file has wrong version 49.0, should be 48.0

Ant does not seem to work with a class file that has a version older than
expected
Has anybody faced the same problem?