I'm neither pro nor con with Kotlin, but let's look at history and parallels.<p>At its peak, Eclipse released Xtend. At that point, Eclipse was the IntelliJ of today, everyone assumed Xtend would be the next Java with full support of Eclipse tooling. Today, well, anyone remembers it? But its still there, check the features: <a href="http://www.eclipse.org/xtend/documentation/index.html" rel="nofollow">http://www.eclipse.org/xtend/documentation/index.html</a>.<p>You will see thousands of articles on kotlin vs java, but only a handful on kotlin vs xtend, because of the cycle.<p>Groovy. Same cycle, same result.<p>Javascript has a large share of syntactic forks. All of them had this hype-cycle. Coffeescript was "de-facto way" to write cross-browser eloquent javascript at one point.<p>There are few lessons from history: Syntactic language forks are what they are - forks. It takes equal amount of tooling and expertise to maintain them. When the next two versions of Java releases, the hype cycle will again turn tides. "X is the better Y", "Groovy is the better Java" - never, there is only one Java, there is no better Java.<p>The best approach is to make the language itself extensible. Look at ES-next and babel. Every language addition is a proposal, and proposals can be implemented as language plugins with stages 3/2/1/0. This effectively rendered most syntactic forks almost meaningless and unnecessary. Have an idea? Extend to the language directly! The most important part - tooling - which is eslint, AST parsing, intermediate representations, code formatting, etc - have been shifted to work on top of language plugins. Now some of you will talk against babel, and how different projects use different babel settings - but given all the history, babel is the best way to pragmatically evolve a language we've ever had so far.<p>Java has a longer mature JSR and language proposal process, just like ES. I really regret that Jetbrains decided to create yet another language fork, while being in the position to create the next babel for java.<p>Will Kotlin be different from all the previous cycles? Only real 2020 will tell, but until then, the only reference available is history.