Go may have more threads, but it is not better at concurrency. It lacks several key things that make Java much easier to scale up, even if Go is easier to get

Go may have more threads, but it is not better at concurrency. It lacks several key things that make Java much easier to scale up, even if Go is easier to get started with. On my wish list: * Thread Local storage. A million Goroutines means nothing is they are all fighting over shared storage. Consider trying to implement Java's LongAdder class, which does intelligent sharding based on contention. * ConcurrentHashMap. sync.Map is horrendously contentious for writes. It's not even possible to write one yourself because Go hides the built in hash function it generates for each type. * Goroutine joining. This is between a rock and a hard place, because if you don't wait till Goroutines are done, you risk leaks, and if you do wait, you need to put WaitGroups all over the place. All those millions of goroutines don't help if you don't have the tools to coordinate them.