I got this when generating documentation with JDK 1.0beta 2:

Generating index
Sorting 20 items . . . done
Generating tree
[parsed /tmp/classsrc/java/lang/String.java in 2418ms]
[parsed /tmp/classsrc/java/lang/RuntimeException.java in 117ms]
[parsed /tmp/classsrc/java/util/Enumeration.java in 147ms]
[parsed /tmp/classsrc/java/io/File.java in 894ms]
[done in 11445ms]
../bin/javadoc -classpath /tmp/classsrc -verbose sun.tools.java
error: Can't read: sun.tools.java
Generating packages.html
Generating index
Sorting 0 items . . . done
^@^@^@^@^@^@^@@^@^@^@^@^@^@^@^@^@^@^@^@^@ [...]
error: An exception has occurred in the compiler; please file a bug report (###@###.###).