http://blogs.sun.com/ahe?entry=update_on_b78#comment1

javac crashes in b78 with NPE in DefaultFileManager:293
$ cat Test.java
public class Test {}
$ new javac -sourcepath /xyz Test.java
An exception has occurred in the compiler (1.6.0-internal). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.NullPointerException
        at com.sun.tools.javac.util.DefaultFileManager.listAll(DefaultFileManager.java:293)
        at com.sun.tools.javac.util.DefaultFileManager.list(DefaultFileManager.java:700)
        at com.sun.tools.javac.jvm.ClassReader.fillIn(ClassReader.java:1954)
        at com.sun.tools.javac.jvm.ClassReader.complete(ClassReader.java:1703)
        at com.sun.tools.javac.code.Symbol.complete(Symbol.java:380)
        at com.sun.tools.javac.comp.Enter.visitTopLevel(Enter.java:259)
        at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:445)
        at com.sun.tools.javac.comp.Enter.classEnter(Enter.java:223)
        at com.sun.tools.javac.comp.Enter.classEnter(Enter.java:237)
        at com.sun.tools.javac.comp.Enter.complete(Enter.java:431)
        at com.sun.tools.javac.comp.Enter.main(Enter.java:416)
        at com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:727)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:634)
        at com.sun.tools.javac.main.Main.compile(Main.java:333)
        at com.sun.tools.javac.main.Main.compile(Main.java:255)
        at com.sun.tools.javac.main.Main.compile(Main.java:246)
        at com.sun.tools.javac.Main.compile(Main.java:70)
        at com.sun.tools.javac.Main.main(Main.java:55)