JShell uses 100% of one core all the time (JDK 15 Build 27)

[Aaron Scott-Boddendijk]

 System:
* Windows 10
* Powershell

When I start JShell, without executing anything, a CPU core is always at
100% (a single thread though I haven't identified what it's doing).

The thread stack is as follows (with only the last two items sometimes
change - but I don't know the internals of the JVM to know if this useful
or significant):

ntoskrnl.exe!KeSynchronizeExecution+0x5b46
ntoskrnl.exe!KeWaitForSingleObject+0x1c2d
ntoskrnl.exe!KeWaitForSingleObject+0xab4
ntoskrnl.exe!KeWaitForSingleObject+0x255
ntoskrnl.exe!RtlClearBitsEx+0x15a7
ntoskrnl.exe!KeWaitForSingleObject+0x3828
ntoskrnl.exe!KeSynchronizeExecution+0x3120
jvm.dll!c2v_notifyCompilerInliningEvent+0x201797

The JDK 14 version of JShell does not have this issue but several of the
recent JDK 15 builds have done this.

--
Aaron Scott-Boddendijk