I get this warning when compiling the JDK:

/home/aioobe/work/oracle/repo/dev/jaxws/src/java.xml.ws/share/classes/com/sun/xml/internal/messaging/saaj/packaging/mime/internet/MimeBodyPart.java:1044: warning: auxiliary class hdr in /home/aioobe/work/oracle/repo/dev/jaxws/src/java.xml.ws/share/classes/com/sun/xml/internal/messaging/saaj/packaging/mime/internet/InternetHeaders.java should not be accessed from outside its own source file
    public FinalArrayList<hdr> getAllHeaders() {
                          ^
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 warning

I suggest moving the "hdr" class to a separate source file (and change the name of the class to something starting with an upper case, like Hdr).