I have tried Dart, It's something like the best of JavaScript and Java in one package. Best of both world, faster compilation time and easy to learn.
Go to dart.dev, everything is perfectly documented and you won't need any tutorial videos if you're familiar with Java.
With Flutter and Hummingbird (flutter on the web), you can dive into front-end development on both mobile and web platform very easily. Learning dart is the best thing you can right now.