Server initialization failed.

[SuperErnD]

[Error - 11:12:11] async0    Internal error: java.lang.IllegalArgumentException: Bad escape
[Error - 11:12:11] java.util.concurrent.CompletionException: java.lang.IllegalArgumentException: Bad escape
[Error - 11:12:11] 	at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315)
[Error - 11:12:11] 	at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320)
[Error - 11:12:11] 	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1770)
[Error - 11:12:11] 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
[Error - 11:12:11] 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
[Error - 11:12:11] 	at java.base/java.lang.Thread.run(Thread.java:833)
[Error - 11:12:11] Caused by: java.lang.IllegalArgumentException: Bad escape
[Error - 11:12:11] 	at java.base/sun.nio.fs.UnixUriUtils.fromUri(UnixUriUtils.java:88)
[Error - 11:12:11] 	at java.base/sun.nio.fs.UnixFileSystemProvider.getPath(UnixFileSystemProvider.java:102)
[Error - 11:12:11] 	at java.base/java.nio.file.Path.of(Path.java:203)
[Error - 11:12:11] 	at java.base/java.nio.file.Paths.get(Paths.java:98)
[Error - 11:12:11] 	at org.javacs.kt.KotlinLanguageServer$initialize$1.invoke(KotlinLanguageServer.kt:123)
[Error - 11:12:11] 	at org.javacs.kt.KotlinLanguageServer$initialize$1.invoke(KotlinLanguageServer.kt:73)
[Error - 11:12:11] 	at org.javacs.kt.util.AsyncExecutor.compute$lambda$2(AsyncExecutor.kt:19)
[Error - 11:12:11] 	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
[Error - 11:12:11] 	... 3 more
[Error - 11:12:11] Server initialization failed.

[themkat]

This usually happens if you have special unicode characters in your path. Possibly a duplicate of #317. Has been an issue with cyrilic and japanese characters at least. If someone wants to look into it, it is probably a good place to start with the path parsing (the special logic was done to fix errors with whitespaces and other characters):
https://github.com/fwcd/kotlin-language-server/blob/main/shared/src/main/kotlin/org/javacs/kt/util/URIs.kt#L15