On Windows the test tools/javac/launcher/SourceLauncherTest.java fails.
This is due to a perennial problem, and manifests when a file is created with a Windows reserved names, please see the following:
https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file?redirectedfrom=MSDN#file_and_directory_names

The error is this:
https://hg.openjdk.java.net/jdk/jdk/file/c1f532e5f910/test/langtools/tools/javac/launcher/SourceLauncherTest.java#l428

Exception running test testNoSourceOnClassPath: java.nio.file.NoSuchFileException: testNoSourceOnClassPath\auxSrc\Aux.java
java.nio.file.NoSuchFileException: testNoSourceOnClassPath\auxSrc\Aux.java
        at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:85)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108)
        at java.base/sun.nio.fs.WindowsFileSystemProvider.newByteChannel(WindowsFileSystemProvider.java:235)
        at java.base/java.nio.file.spi.FileSystemProvider.newOutputStream(FileSystemProvider.java:478)
        at java.base/java.nio.file.Files.newOutputStream(Files.java:219)
        at java.base/java.nio.file.Files.newBufferedWriter(Files.java:2919)
        at java.base/java.nio.file.Files.newBufferedWriter(Files.java:2962)
        at toolbox.ToolBox$JavaSource.write(ToolBox.java:636)
        at toolbox.ToolBox.writeJavaFiles(ToolBox.java:565)
        at SourceLauncherTest.testNoSourceOnClassPath(SourceLauncherTest.java:269)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at toolbox.TestRunner.runTests(TestRunner.java:89)
        at SourceLauncherTest.main(SourceLauncherTest.java:63)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
        at java.base/java.lang.Thread.run(Thread.java:834)

Here is an example using java source launcher:

$ cat Test.java
import java.io.*;
import java.nio.file.*;
public class Test {
    public static void main(String... args) throws Exception {
if (args == null || args.length < 1) {
            throw new Error("Usage: need one pathspec argument");
}
        Path file = Path.of(args[0]);
Files.createDirectories(file.getParent());
try (BufferedWriter out = Files.newBufferedWriter(file)) {
            out.write("An auk or alcid is a bird of the family of Alcidae.");
}
    }
}

$ BLAH/images/jdk/bin/java Test.java foo/Aux.java
Exception in thread "main" java.nio.file.NoSuchFileException: foo\Aux.java
        at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:85)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108)
        at java.base/sun.nio.fs.WindowsFileSystemProvider.newByteChannel(WindowsFileSystemProvider.java:235)
        at java.base/java.nio.file.spi.FileSystemProvider.newOutputStream(FileSystemProvider.java:478)
        at java.base/java.nio.file.Files.newOutputStream(Files.java:219)
        at java.base/java.nio.file.Files.newBufferedWriter(Files.java:2919)
        at java.base/java.nio.file.Files.newBufferedWriter(Files.java:2962)
        at Test.main(Test.java:16)

$ BLAH/images/jdk/bin/java Test.java foo/Auk.java
$ cat foo/Auk.java
An auk or alcid is a bird of the family of Alcidae.


So changing the name from Aux.java or class Aux to Auk will work for the test. I am not sure why javac did not catch this please see JDK-6241975.

I discovered this with jdk11.0.8 and why hasn't anyone else encountered this issue ?

My suggestion is to enhance toolbox and other test helpers to check for these reserved keywords and warn the developer up front.

Running on Windows Server 2016.