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MANIFEST.MF file

 
Kevin Mc Cusker
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Hello there. Im new here and ive just downloaded the Boggitt & Scarper assignment. Could somebody please tell me what the Manifest.mf file is? Also, im a little unsure about what im allowed/supposed to do with the db-2x1 file. To what extent am i allowed to change it or do i need to find a means of manipulating the contents without changing the format? After reading the instructions im reluctant to try anything through fear of doing something "WRONG"!! Help.
 
Kevin Mc Cusker
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hmmm. so its not important. no news is good news my old ma used to say.
 
Niall ORiordan
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Not sure what the manifest file is. I would imagine it is something with do with Jarring of the jar file you downloaded...That is what manifest files do.
As for your other question....
Take a copy of the .dat file...
DO NOT USE THE ORIGINAL TO MEES AROUND WITH or you will have to download the assignment again. Otherwise feel free to do what you like. Good luck.
 
Damian Ryan
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Mark, Niall
The manifest.mf file is a metadata file found in all JAR files. It contains key-value pair type entries, and, at a minimum tends to record the version of the JAR specification used by the archive (this is from memory, so I could be mistaken).
The entries in a manifest file have several purposes, but the one you are most likely to encounter later in your assignment is the Main-Class attribute, which you can use to make an executable JAR file. For example, if your main executable class was com.foo.bar.Clazz, you would have an entry in the manifest.mf file of your archive (called, say, my_archive.jar) like this:

then if you typed

the archive would be loaded and the main method in com.foo.bar.Clazz would be executed by the JVM. Packaging classes like this is helpful because it can avoid the need to state a classpath (either with the CLASSPATH environment variable or with the "-cp" option of the java command) because you can putt all the classes you will need into the JAR.
The manifest.mf file that comes inside the archive containing your assignment probably only contains a couple of entries about versioning information. You don't need to pay it any attention.
Hope this helps.
 
Kevin Mc Cusker
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cheers niall & damian. ill get stuck right into this baby now. speak soon.
 
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