Cannot run buck project on OpenJDK11 when target_level = 11

Created by: davidtron

Cannot generate buck project when using java 11 source and target levels (either command line or .buckconfig)

[java]
    source_level = 11
    target_level = 11
    jar_spool_mode = direct_to_jar

Java Version : OpenJDK 11.0.3 Buck release : v2019.09.12.01

Results in

Buck encountered an internal error

java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:221)
	at com.facebook.buck.jvm.java.JavaFileParser.createJavaFileParser(JavaFileParser.java:459)
	at com.facebook.buck.features.project.intellij.IjProjectCommandHelper.writeProjectAndGetRequiredBuildTargets(IjProjectCommandHelper.java:263)
	at com.facebook.buck.features.project.intellij.IjProjectCommandHelper.runIntellijProjectGenerator(IjProjectCommandHelper.java:221)
	at com.facebook.buck.features.project.intellij.IjProjectCommandHelper.parseTargetsAndRunProjectGenerator(IjProjectCommandHelper.java:208)
	at com.facebook.buck.features.project.intellij.IjProjectSubCommand.run(IjProjectSubCommand.java:211)
	at com.facebook.buck.cli.ProjectCommand.runWithoutHelp(ProjectCommand.java:146)
	at com.facebook.buck.cli.AbstractCommand.run(AbstractCommand.java:257)
	at com.facebook.buck.cli.AbstractContainerCommand.run(AbstractContainerCommand.java:81)
	at com.facebook.buck.cli.MainRunner.runMainWithExitCode(MainRunner.java:1344)
	at com.facebook.buck.cli.MainRunner.runMainThenExit(MainRunner.java:456)
	at com.facebook.buck.cli.MainWithNailgun.nailMain(MainWithNailgun.java:76)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at com.facebook.nailgun.NGSession.runImpl(NGSession.java:313)
	at com.facebook.nailgun.NGSession.run(NGSession.java:199)