While compiling hello world (a regression from jdk8u72)
(build 9-ea+100-2016-01-06-195905.javare.4235.nc)

$ javac -sourcepath / Main.java

An exception has occurred in the compiler (9-ea). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.NullPointerException
at com.sun.tools.javac.file.JavacFileManager.listContainer(JavacFileManager.java:428)
at com.sun.tools.javac.file.JavacFileManager.list(JavacFileManager.java:568)
at com.sun.tools.javac.code.ClassFinder.scanUserPaths(ClassFinder.java:579)
at com.sun.tools.javac.code.ClassFinder.fillIn(ClassFinder.java:513)
at com.sun.tools.javac.code.ClassFinder.complete(ClassFinder.java:295)
at com.sun.tools.javac.code.ClassFinder.access$000(ClassFinder.java:74)
at com.sun.tools.javac.code.ClassFinder$1.complete(ClassFinder.java:166)
at com.sun.tools.javac.code.Symbol.complete(Symbol.java:590)
at com.sun.tools.javac.comp.Enter.visitTopLevel(Enter.java:299)
at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:509)
at com.sun.tools.javac.comp.Enter.classEnter(Enter.java:255)
at com.sun.tools.javac.comp.Enter.classEnter(Enter.java:270)
at com.sun.tools.javac.comp.Enter.complete(Enter.java:483)
at com.sun.tools.javac.comp.Enter.main(Enter.java:467)
at com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:962)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:839)
at com.sun.tools.javac.main.Main.compile(Main.java:257)
at com.sun.tools.javac.main.Main.compile(Main.java:142)
at com.sun.tools.javac.Main.compile(Main.java:56)
at com.sun.tools.javac.Main.main(Main.java:42)