Can anyone explain to me the apparently only-partial support for java
1.5 in Eclipse (3.1m4)?  Legal 1.5 code fails in Eclipse - autoboxing
specifically seems problematic.  Why would that happen?  Isn't eclipse
using my java 1.5 sdk when it does its builds? For example, this code
compiles just fine from the command line:

String theStr = null;
Integer theInt = theStr == null ? 1 : null;
System.out.println("theInt=" + theInt)

But when I throw it into an Eclipse scrap page (for example) and try to
compile and execute it, I get the following error:

Incompatible conditional operand types int and null

My "compiler compliance level" is set to 5.0.  My Installed JRE is set
to the same JRE used by my command-line builds.
(Is there a better place to ask this?)