(In the interests of full disclosure we did originally opt for Scala, with a few caveats and a recommended reading list for the features to avoid or use sparingly).
I had already started reading Functional Programming in Java 8, but I think now is a good opportunity to look back over the features of the language and consider where there are particular strengths and weaknesses.
This post will only focus on Core Java - not Java Enterprise Edition, Swing or any frameworks.
- Labeled break / continue
- These expressions are the closest you can get to having a goto in Java
- Checked Exceptions
- I haven't quite convinced myself about this one yet, but I have a particular dislike for having to wrap a call with a try / catch block where the catch block only contains a comment like // can never happen
- All too often exceptions are used to control flow for scenarios that aren't truly exceptional
- Reflection
- Generally prevents the compiler from having static access to the relationships between classes.
- On the flip side, static analysis tools can be expected to make use of reflection.
- Local classes
- Did you know that you can declare a class inside any block? Not just anonymous classes, but even fully fledged named classes.
- instanceof
- Whenever I find myself introducing an instanceof check in my code I feel like there must be a better way.
- Restrictions on Generics
- I think this is well covered by the Java tutorial: http://docs.oracle.com/javase/tutorial/java/generics/restrictions.html
Runtime gotchas
- Memory allocation
- Out of memory exception - particularly PermGen space, and particularly when reflection or dynamic class loading is involved - before Java 8.
- Garbage collection
- Stop the world - collecting large accumulated garbage while blocking other progress.
Sorry for the lack of substance, but sometimes this blog exists as a checklist of reminders for myself. I haven't Googled a problem and reached my own blog yet, but I can imagine it will only be a matter of time.
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