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I like Kotlin (as a half-way house in a Java codebase to something purer like Scala) but I'm worried about being locked in in future, and that becoming a liabil

I like Kotlin (as a half-way house in a Java codebase to something purer like Scala) but I'm worried about being locked in in future, and that becoming a liability in a codebase 20 years from now. Does anyone have experience of emergency automatic conversion back to Java? (Edit: Never used Kotlin but I like the look of it)

mrkeen 7y ago
It sounds like you got locked in.
- afandian 7y ago
  Locked into Java, yes. At some level it's unavoidable, you have to choose some kind of stack. And of course there are different kinds of ways to get out of lock-in. One of them is being able to convert to a common 'lower' language. I've not used Kotlin but I would be more likely to if I knew that avenue was practical.
thu2111 7y ago
There's no direct conversion back. IntelliJ has a decompiler that produces reasonable-ish Java code based on the debug symbols, so you get things like local variable names and obviously method/class names back, but, it's a decompiler, so no code comments. And Kotlin constructs frequently require synthetic Java variables to be created that were implicit in the Kotlin, so you have to clean up the result quite a bit. However note that Kotlin and Java code can co-exist very closely in the same codebase. In the same way you can incrementally port a Java codebase to Kotlin, so too can you incrementally port Kotlin to Java. There's just no automatic tool for it like there is Java->Kotlin.
- afandian 7y ago
  Thanks for that. I think I'd misread something then and thought that it could work both ways.
jillesvangurp 7y ago
I think the reason a Kotlin to Java converter does not exist is mainly because there's simply no demand for it in the Kotlin community. In my experience it's a one way street and people generally have no desire whatsoever to go back after they start converting Java code to Kotlin. There's nothing particularly hard about it; it all compiles down to the same bytecode. People keep bringing up Scala as a "purer" language. This seems to be true in the minds of Scala purists mainly. I've done Scala, IMHO it's a very messy language that seems to result in unwieldy code bases that was made for wannabe functional programmers that need a halfway house on the way to a proper functional language (like Haskell or Elixir).

mrkeen 7y ago

It sounds like you got locked in.

afandian 7y ago
Locked into Java, yes. At some level it's unavoidable, you have to choose some kind of stack. And of course there are different kinds of ways to get out of lock-in. One of them is being able to convert to a common 'lower' language. I've not used Kotlin but I would be more likely to if I knew that avenue was practical.

thu2111 7y ago

There's no direct conversion back. IntelliJ has a decompiler that produces reasonable-ish Java code based on the debug symbols, so you get things like local variable names and obviously method/class names back, but, it's a decompiler, so no code comments. And Kotlin constructs frequently require synthetic Java variables to be created that were implicit in the Kotlin, so you have to clean up the result quite a bit. However note that Kotlin and Java code can co-exist very closely in the same codebase. In the same way you can incrementally port a Java codebase to Kotlin, so too can you incrementally port Kotlin to Java. There's just no automatic tool for it like there is Java->Kotlin.

afandian 7y ago
Thanks for that. I think I'd misread something then and thought that it could work both ways.

jillesvangurp 7y ago

I think the reason a Kotlin to Java converter does not exist is mainly because there's simply no demand for it in the Kotlin community. In my experience it's a one way street and people generally have no desire whatsoever to go back after they start converting Java code to Kotlin. There's nothing particularly hard about it; it all compiles down to the same bytecode. People keep bringing up Scala as a "purer" language. This seems to be true in the minds of Scala purists mainly. I've done Scala, IMHO it's a very messy language that seems to result in unwieldy code bases that was made for wannabe functional programmers that need a halfway house on the way to a proper functional language (like Haskell or Elixir).