IDEA has offered checks for Null/Not Null since annotations were available as language feature. After a decade this feature is also available in Eclipse, but of course it was implemented in a way that is incompatible with IntelliJ.
Unfortunately, the reality in real-life projects is that there are a lot of Eclipse users on the team and now that this kind of check is available natively in Eclipse, they want to use them in projects. The differences that I have found so far are small. It would be really nice if IDEA 13 could inlcude checks that are fully compatible with Eclipse.
I have already filed a couple of issues (IDEA-114883, IDEA-114884, IDEA-114889, IDEA-114891, IDEA-114892) and it would be great if others could add more incompatiblities when they spot them. Hey, I even downloaded and installed Eclipse to find out about these problems.
It would also be nice if IDEA-65566 could be implemented for IDEA 13. However, I'm not a big fan of the this one. I believe that the definition of org.eclipse.jdt.annotation.NonNullByDefault of Eclipse is not fully compatible with javax.annotation.ParametersAreNonnullByDefault and also not fully compatible with the annotation that is used in Google Guava. It's a shame that JSR305 wasn't completed.
Also, it might be worth adding the possibility to have more than one @NotNull/@Nullable annotation. This could be the useful when one uses libraries that use the Eclipse style annotations and others that use jsr305 annotations. What do you guys think?