It's probably more complicated than that.
In the old days, BEA/WebLogic - the predecessor for many of these products - would let you download a free evaluation copy with a 60 or 90 day run period. After which the product ceased to operate unless you bought a key.
Since then, pressures from open-source products (such as
JBoss) have caused Oracle and IBM to release "Community Edition" versions of their products. These are often full-featured implementations - minus some of the Enterprise-grade bells and whistles (for example, I think DB2 CE is limited to a "mere" 1 GB of RAM usage). Some of these may be open to commercial use, since they figure that if you need it bad enough, eventually you'll start paying for support and/or the high-end features.
Then there are academic licenses, which may carry slightly different restrictions.
Unfortunately, I can't tell what licenses are available for the products in question.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.