These days Java isn't slow to develop on at all. There are plenty of very good frameworks where you can get going with developing a web app or rest service in next to no time with far better tooling support, sophistication etc.
.NET is a serious contender though.
Node isn't really on the same ballpark in terms of maturity.
It the other way around. Java has barely caught up with C#. C# team is typically introducing more features, faster.
I prefer Java's more thoughtful approach to introducing new features.
In addition, green threads approach is a strictly worse and a more limited solution that only solves thread blocking without unlocking the variety of terse concurrency patterns enabled by the way the tasks are handled in .NET. They also add significant overhead to interop with native code due to thread pinning/stack switching (also applies to Go).