There are many articles and blog posts about this topic but rarely are they complete. I’ll cover finalizers, Finalizer Guardian idiom, Dispose Pattern, PhantomReference and Cleanable.
Continue reading “How to replace Object.finalize()”
Run code only once!
Project hosted on github: https://github.com/claudemartin/LockOnce
It’s just one single utility class to make sure code is run only once. And then there’s another one for easy “Lazy Initialization”.
I once wrote this for Java 7 but now it needs Java 8. It makes much more sense to use this with Lambdas. It’s a bit like the lazy keyword of Scala.
// declaration of lazy field:
final Supplier<Foo> lazy = Lazy.of(() -> ...);
// Access to the data:
Foo foo = lazy.get();
You can also register a “destructor”. This solves the problem that such fields (they are usually
static final) are never GCd and finalizers are utterly useless. In the same way you can have resources (they just have to implement
AutoClose) closed on shutdown.
There already is
sun.misc.Cleaner. And Java 9 should even have
java.util.Cleaner or something like that. I simply didn’t know. So it’s better to wait for Java 9 or use
If you are still interested:
I have a blog post about Finalizers and PhantomReferences:
I did this because
EnumSet is in fact a bit set (if it’s not a
JumboEnumSet) but it can’t be used as such. I ended up writing a complete library for domain bit sets.
Project website: http://claude-martin.ch/enumbitset/
Project home @ GitHub: https://github.com/claudemartin/enum-bit-set