Unexpected runtime failure w/ google-java-format + native-image

[perezd]

Here's the crash I'm getting:

./core/src/main/java/com/google/googlejavaformat/Output.java: error: null
java.lang.ExceptionInInitializerError
	at com.sun.tools.javac.file.BaseFileManager.createLocations(BaseFileManager.java:115)
	at com.sun.tools.javac.file.BaseFileManager.<init>(BaseFileManager.java:76)
	at com.sun.tools.javac.file.JavacFileManager.<init>(JavacFileManager.java:144)
	at com.google.googlejavaformat.java.JavaInput.buildToks(JavaInput.java:352)
	at com.google.googlejavaformat.java.JavaInput.buildToks(JavaInput.java:334)
	at com.google.googlejavaformat.java.JavaInput.<init>(JavaInput.java:276)
	at com.google.googlejavaformat.java.Formatter.getFormatReplacements(Formatter.java:260)
	at com.google.googlejavaformat.java.Formatter.formatSource(Formatter.java:247)
	at com.google.googlejavaformat.java.FormatFileCallable.call(FormatFileCallable.java:45)
	at com.google.googlejavaformat.java.FormatFileCallable.call(FormatFileCallable.java:26)
	at java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.lang.Thread.run(Thread.java:829)
	at com.oracle.svm.core.thread.JavaThreads.threadStartRoutine(JavaThreads.java:596)
	at com.oracle.svm.core.posix.thread.PosixJavaThreads.pthreadStartRoutine(PosixJavaThreads.java:192)
Caused by: java.lang.NullPointerException
	at sun.nio.fs.UnixPath.normalizeAndCheck(UnixPath.java:75)
	at sun.nio.fs.UnixPath.<init>(UnixPath.java:69)
	at sun.nio.fs.UnixFileSystem.getPath(UnixFileSystem.java:279)
	at com.sun.tools.javac.file.Locations.<clinit>(Locations.java:139)

Reproducer:
https://github.com/perezd/google-java-format/tree/native-image

how to build:

mvn -Pnative -DskipTests package

Then simply run and observe failure like so:

./core/target/google-java-format ./core/src/main/java/com/google/googlejavaformat/Output.java

Any suggestions on how to get this working? I'm kinda lost.

[perezd]

Ah, looks like this could be the root cause:

static final Path javaHome = FileSystems.getDefault().getPath(System.getProperty("java.home"));

[perezd]

How should this normally be managed? if I specify -Djava.home=/path it seems to get past the error and onto a new one, but wondering how this is generally dealt with.

[perezd]

I've tried adding:

<buildArgs>-Djava.home=${java.home}</buildArgs>

but does not seem to stick as I'd expect.

[cushon]

There's an open issue for handling standard system properties like java.home: #2835

For this specific use-case, we can use --initialize-at-build-time=com.sun.tools.javac.file.Locations as a workaround. We don't actually rely on the value of java.home, and initializing it at build time avoids the crash.