Internal error when execute debugging

When I execute debugging, an internal error occur. And in debug console, it says,

```
[INFO] main Connected to client
[INFO] async1 Could not resolve kotlin-stdlib using Maven: null
[INFO] async1 Could not resolve kotlin-stdlib using Gradle: C:\Users\xxx\.gradle\caches
[INFO] async1 Could not resolve kotlin-stdlib using Maven: null
[INFO] async1 Could not resolve kotlin-stdlib using Gradle: C:\Users\xxx\.gradle\caches
[INFO] async1 Starting JVM debug session with main class main
[ERROR] async1 Internal error: java.lang.UnsupportedOperationException: Empty collection can't be reduced.
[ERROR] java.util.concurrent.CompletionException: java.lang.UnsupportedOperationException: Empty collection can't be reduced.
[ERROR] at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:314)
[ERROR] at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:319)
[ERROR] at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1810)
[ERROR] at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
[ERROR] at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
[ERROR] at java.base/java.lang.Thread.run(Thread.java:830)
[ERROR] Caused by: java.lang.UnsupportedOperationException: Empty collection can't be reduced.
[ERROR] at org.javacs.ktda.jdi.launch.JDILauncher.formatClasspath(JDILauncher.kt:119)
[ERROR] at org.javacs.ktda.jdi.launch.JDILauncher.formatOptions(JDILauncher.kt:88)
[ERROR] at org.javacs.ktda.jdi.launch.JDILauncher.createLaunchArgs(JDILauncher.kt:58)
[ERROR] at org.javacs.ktda.jdi.launch.JDILauncher.launch(JDILauncher.kt:37)
[ERROR] at org.javacs.ktda.jdi.launch.JDILauncher.launch(JDILauncher.kt:24)
[ERROR] at org.javacs.ktda.adapter.KotlinDebugAdapter$launch$1.invoke(KotlinDebugAdapter.kt:111)
[ERROR] at org.javacs.ktda.adapter.KotlinDebugAdapter$launch$1.invoke(KotlinDebugAdapter.kt:37)
[ERROR] at org.javacs.kt.util.AsyncExecutorKt$sam$java_lang_Runnable$0.run(AsyncExecutor.kt)
[ERROR] at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1807)
[ERROR] ... 3 more
```

and my `launch.json`

```
"version": "0.2.0",
"configurations": [
{
"type": "kotlin",
"request": "launch",
"name": "Kotlin Launch",
"projectRoot": "${workspaceFolder}",
"mainClass": "main"
}
]
```