[Enhanced switch] BootstrapMethodError: bootstrap method initialization exception switching on Boolean

[srikanth-sankaran]

Master:

There are at least two problems here:

1. This code should not compile at 23, without preview enabled. It does.
2. When run it reports:

Exception in thread "main" java.lang.BootstrapMethodError: bootstrap method initialization exception
	at java.base/java.lang.invoke.BootstrapMethodInvoker.invoke(BootstrapMethodInvoker.java:188)
	at java.base/java.lang.invoke.CallSite.makeSite(CallSite.java:316)
	at java.base/java.lang.invoke.MethodHandleNatives.linkCallSiteImpl(MethodHandleNatives.java:274)
	at java.base/java.lang.invoke.MethodHandleNatives.linkCallSite(MethodHandleNatives.java:264)
	at X.main(X.java:4)
Caused by: java.lang.IllegalArgumentException: label with illegal type found: class java.lang.Boolean
	at java.base/java.lang.runtime.SwitchBootstraps.verifyLabel(SwitchBootstraps.java:172)
	at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:1024)
	at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762)
	at java.base/java.lang.runtime.SwitchBootstraps.typeSwitch(SwitchBootstraps.java:156)
	at java.base/java.lang.invoke.BootstrapMethodInvoker.invoke(BootstrapMethodInvoker.java:147)
	... 4 more

public class X {
 public static void main(String[] args) {
	 Boolean b = null;
	 switch (b) {
	 	case true -> System.out.println("true");
	 	case false -> System.out.println("false");
	 	case null -> System.out.println("Null");
	 }
 }
}

[srikanth-sankaran]

Confusingly, javac from JDK23 also compiles this without preview being enabled and also crashes with identical symptoms

Likewise with JDK24 early access build 26

[srikanth-sankaran]

Javac from JDK21 complains:

5: error: constant label of type boolean is not compatible with switch selector type Boolean
case true -> System.out.println("true");

Likewise with javac from JDK22