Some IDEs show type hints on hover, or if type mismatch is detected, they display inferred types inline in code. E.g Intellij Idea does that for Scala and it is

Some IDEs show type hints on hover, or if type mismatch is detected, they display inferred types inline in code. E.g Intellij Idea does that for Scala and it is really useful. I wish it did that in Java as well.