MIME : Java Glossary

MimeCheck

This Applet will tell you what your server is sending for MIME types and what it should be. If you discover errors in the what it server is sending, notify the ISP (Internet Service Provider). If you discover errors in what the MIME type should be, email me at .

Java Requirements and Troubleshooting

MimeCheck is a signed Java Applet (that can also be run as an application) to MIME Check. You are welcome to install it on your own website. If it does not work…

1. For this Applet hybrid to work, you must click grant/accept/always run on this site/I accept the risk to give it permission to read from any server on the web. If you refuse to grant permission, the program may crash with an inscrutable stack dump on the console complaining about AccessController.checkPermission.
2. In the Java Control Panel security tab, click Start ⇒ Control Panel ⇒ Programs ⇒ Java ⇒ Security, configure medium security to allow self-signed and vanilla unsigned applets to run. If medium is not available, or if Java security is blocking you from running the program, configure high security and add http://mindprod.com to the Exception Site List at the bottom of the security tab.
3. Often problems can be fixed simply by clicking the reload button on your browser.
4. Make sure you have both JavaScript and Java enabled in your browser.
5. Make sure the Java in your browser is enabled in the security tab of the Java Control panel. Click Start ⇒ Control Panel ⇒ Programs ⇒ Java ⇒ Security ⇒ Enable Java Content in the browser.
6. This signed Java Applet (that can also be run as an application) needs 32-bit or 64-bit Java 1.8 or later. For best results use the latest 1.8.0_131 Java.
7. You also need a recent browser.
8. It works under any operating system that supports Java e.g. W2K, XP, W2003, Vista, W2008, W7-32, W7-64, W8-32, W8-64, W2012, W10-32, W10-64, Linux, LinuxARM, LinuxX86, LinuxX64, Ubuntu, Solaris, SolarisSPARC, SolarisSPARC64, SolarisX86, SolarisX64 and OSX
9. You should see the Applet hybrid above looking much like this screenshot. If you don’t, the following hints should help you get it working:
10. Optionally, you may permanently install the Canadian Mind Products code-signing certificate so you don’t have to grant each time.
11. If the above Applet hybrid appears to freeze-up, click Alt-Esc repeatedly to check for any buried permission dialog box.
12. If you have certificate troubles, check the installed certificates and remove or update any obsolete or suspected defective certificates. The only certificate used by this program is mindprodcert2017rsa.cer.
13. Especially if this Applet hybrid has worked before, try clearing the browser cache and rebooting.
14. To ensure your Java is up to date, check with Wassup. First, download it and run it as an application independent of your browser, then run it online as an Applet to add the complication of your browser.
15. If the above Applet hybrid does not work, check the Java console for error messages.
16. If the above Applet hybrid does not work, you might have better luck with the downloadable version available below.
17. If you are using Mac OS X and would like an improved Look and Feel, download the QuaQua look & feel from randelshofer.ch/quaqua. UnZip the contained quaqua.jar and install it in ~/Library/Java/Extensions or one of the other ext dirs.
18. Upgrade to the latest version of Internet Explorer or another browser.
19. Click the Information bar, and then click Allow blocked content. Unfortunately, this also allows dangerous ActiveX code to run. However, you must do this in order to get access to perfectly-safe Java Applets running in a sandbox. This is part of Microsoft’s war on Java.
20. Try upgrading to a more recent version of your browser, or try a different browser e.g. Firefox, SeaMonkey, IE or Avant.
21. If you still can’t get the program working click the red HELP button below for more detail.
22. If you can’t get the above Applet hybrid working after trying the advice above and from the red HELP button below, have bugs to report or ideas to improve the program or its documentation, please send me an email at.

   Get New Java   Get New Browser  

MIME types are referred to in the RFC 1945 HTTP 1.0 specification as media types types. The content-type and content-encoding fields in the RFC 1945 HTTP header together give a hint to the receiver what kind of data has just been handed to it.

IANA is responsible for assigning new MIME types. Unfortunately naming is even more chaotic than the extensions, often with several conflicting MIME types for each extension. Unfortunately, MIME has made the problem it was intended to solve even worse. It matters not what the official name is, but the MIME name configured in the majority of the world’s browsers is. I have found Filext.com the most useful source.

The Printable Problem

• 7bit (unencoded, case-insensitive, the data are all represented as short lines of US-ASCII data)
• quoted-printable (best used when message is mostly plain text with a few strange characters)
• base64
• uuencode
• 8bit (unencoded, the lines are short, but there may be non-ASCII characters)
• binary (unencoded, any characters, lines may be long) not used in practice.
• x-token

Eventually this printable encoding will be dropped. Base64 encoding, for example, adds 33% overhead to the transmitted message size. The Internet is now almost completely converted to 8-bit, so it should not usually be necessary.

MIME Types For A Java Website

There is a database of MIME types and extensions in the Windows Registry. At some point I will mine it for more entries. HKEY_CLASSES_ROOT\ MIME \Database\Content Type\application/x-java-jnlp-file. You can get a list of Windows extensions and associated MIME types by typing assoc at the command prompt.

HTML (Hypertext Markup Language) forms use application/x-www-form-urlencoded, though there is no filename.

MIME Hate

• The whole MIME scheme is disorganised. What determines how your browser displays, executes or downloads any given URL (Uniform Resource Locator) depends on its extension, the MIME type the website assigned that extension, the MIME type your browser assigned that extension and the MIME type your operating system assigned that extension, the program your browser assigned to that MIME type and the program your operating system assigned to that MIME type and probably the current phase of the moon.
• There is no way to attach a MIME type to a file. It has to be generated from the extension anyway with tables maintained on the server. There is no way to deal with files with different MIME types but the same extension anyway. MIME fails in its primary objective.
• Some websites ignore MIMEs entirely and call everything text/plain.
• There are duplicate MIME names for the same file type.
• There is no official list of MIME names anywhere.
• There is no one in charge of assigning MIME names. IANA (Internet Assigned Numbers Authority) supposedly is, but they don’t seem to keep properly formatted records about MIME names, their extensions and uses, they don’t assign names to avoid duplicates.
• There are many file types without assigned MIME names.
• MIME names are long-winded.
• MIME 7-bit encoding wastes bandwidth.
• MIME types are mapped from extensions to MIME types on a global, one-size-fits-all website-wide basis. The whole point of MIME types was to resolve the ambiguity of the same extension being used for two different purposes. To work properly MIME types need to be attached to files, just the way their human names are.

MIME Sources

You can get the MIME type for a given file using java.net.FileNameMap.getContentTypeFor(filename)

Here is one offial source for MIME types: The definitive IANA list however it has only a fraction of the total is use.

Configuring the Server

Programs To Handle Video and Audio Streams

Possible video download formats

Video Links Legend
streaming or downloadable
Click corresponding icon to download player.
Apple QuickTime
BitTorrent
DailyMotion
DivX
DVD
Flash animations
Google
HTML5
Microsoft Media Player
Microsoft Power Point
mpg
mp3
mp4
Real Player
Shockwave
VHS tape
Vimeo online video
YouTube
unknown
lyrics
transcript

Audio Links Legend
streaming or downloadable
Click corresponding icon to download player.
Real Audio
Flash
compressed mp3
super compressed mp4
Microsoft Media Player
MIDI music files
uncompressed au
Microsoft uncompressed wav
unknown
lyrics
transcript

JAF (Java Activation Framework) built-in MIME Types

1. Programmatically added entries to the MimetypesFileTypeMap instance.
2. The file .mime.types in the user’s home directory.
3. The file C:\Program Files\java\jre1.8.0_131\ /lib/mime.types.
4. The resource named META-INF/mime.types.
5. The resource named META-INF/mimetypes.default in the activation.jar file.

Local Files

Learning More

• RFC 2045: MIME part 1
• RFC 2049: MIME part 2, non ASCII
• RFC 2045 MIME Part One: Format of Internet Message Bodies, specifies the various headers used to describe the structure of MIME messages.
• RFC 2046 MIME Part Two: Media Types, describes the general structure of the MIME media typing system and defines an initial set of media types.
• RFC 2047 MIME Part Three: Message Header Extensions for non-ASCII text
• RFC 6838 and RFC 4289 MIME Part Four: Registration Procedures
• RFC 2049 MIME Part Five: Conformance Criteria and Examples, Provides some illustrative examples of MIME message formats