Resources to learn AS3?

I hear that Java is very similar to AS3 so should I go learning more Java? Or go for learning pure AS3?

First off, you are comparing a scripting language (AS3) to Java (compiled language)

It depends on what you are trying to do.

If you are beginner I suggest start with Action-script or Java-script not Java.

Actionscript is object-oriented. However, Java more useful in the long run. Java is a high-level programming language .

learn the language you want to learn, learning 1 language to help with a completely different one will take much longer
afaik java and flash are much different but ive never focused on java, only javascript

To be completely honest c# and as3 are very similar if you're learning coding for purely rotmg i recommend learning c# then getting into as3 when you're c# fluent