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> Type information literally doesn't exist at runtime, though. Correct if I'm wrong, not all types get erased in Java. Doesn't type erasure only happen for gen
by lopatin 8y ago
> Type information literally doesn't exist at runtime, though.
Correct if I'm wrong, not all types get erased in Java. Doesn't type erasure only happen for generics? Say I have a non generic, plain Java class and want to inspect one of it's method's return types at runtime to see if it returns class A or class B. I can do that, right?
- stickfigure 8y agoYes, you are correct. There are also a number of circumstances in which you can get generic type info - it isn't erased, for example, if you create a concrete subclass of a generic type.
- pitaj 8y agoI was talking about JavaScript. In JavaScript there are no typed functions or arguments, so that information doesn't exist period.
- lopatin 8y agoRight, so I guess I'm not understanding your point about why comparing two languages like this is ridiculous. Java has a full blown runtime reflection system (it's "types exist at runtime"). JS doesn't. So Java wins in the reflection category.
- tracker1 8y agoBut in JS, reflection is pretty much not needed... I don't need to use reflection to see if an object has a quack method, or that I call it with the right types... I just call instance.quack() ... It's up to you as the developer to keep your interfaces and composition in line. It's actually WAY easier than with C# or Java. Since the use-case of reflection itself is largely unnecessary.
- lopatin 8y agoCalling a method and seeing what happens is not a substitute for reflection. You can do that in Java too btw.