Minecraft Forums

The location of version.json is at
http://s3.amazonaws....s/versions.json.
This file contains a list of all the minecraft versions, as well as which one is the latest version.

The settings that one could do with all the data from this tutorial, if not more, could be:

• CMD Screen, Whether to display it or not.

java
javaw

• Starting Ram, The ram can increment by measurements of 512.

-Xms512m

• Max Ram

-Xmx1024m

• What version to play.

1.6.2
1.5.2
alpha
beta
etc

• Where to place the saves/mods/configs separate from other profiles.

• Where to save the .minecraft files.

• Whether to play offline or online. Include or exclude the Session ID from the command line.

When you click the login button, the very next thing the launcher does is probably to check online to see if you have logged in recently and compare if your current session is still valid. If not, it might save an expiration date and compare against it. If you don't have a Session ID yet, it will then of course login to https://login.minecraft.net/ and retrieve it.

More info can be found here.
---------------------------------------------------------------------------
The New Method
As of 1.6 they changed how the session ID works. Its now referred to as the "Client Token", "Access Token", and the "UUID"

This new method can be used in place of the Session ID for all versions. So as to maintain backwards compatibility, I assume.

As of 1.7 Its now required.

For how to use these new Tokens proceed to reading this and read to step 5.

This file can be found in the same place as the ".jar". The location is at
http://s3.amazonaws.....6.2/1.6.2.jsonWhere it says 1.6.2 it can be replaced by any version you might have chosen from the settings menu in the past. So for example, if you decided you want to play "b1.7.3" then that might read as
http://s3.amazonaws....7.3/b1.7.3.json.
This file is usually saved in the versions folder.

C:\LOCATION\.minecraft\versions\1.6.2\1.6.2.json

This file contains data needed for the command line, native files, and library files.

The command line needs the value from minecraftArguments and mainClass.

In minecraftArguments you should see text that looks like "${text}." What those are used for should be fairly straight forward. But, if you don't know, it replaces those segments with the appropriate data from earlier. So, for example: We start with

--username ${auth_player_name} --session ${auth_session} --version ${version_name} --gameDir ${game_directory} --assetsDir ${game_assets}

Or

--username ${auth_player_name} --version ${version_name} --gameDir ${game_directory} --assetsDir ${game_assets} --uuid ${auth_uuid} --accessToken ${auth_access_token}

and should end up with something close to this

--username TrinaryAtom --session 44324328965854839543 --version 1.6.2 --gameDir "C:\LOCATION\.minecraft" --assetsDir "C:\LOCATION\.minecraft\assets"

Or this

--username TrinaryAtom --version 1.7.2 --gameDir "C:\LOCATION\.minecraft" --assetsDir "C:\LOCATION\.minecraft\assets" --uuid 2321dufh7892hfes79y --accessToken fdshg7843y78gsdf9fd

• ${auth_player_name}

is replaced with the players username. (I suggest using the one from login.minecraft.net, to be more precise.)

• ${auth_session}

is replaced with the Session ID retrieved from login.
----------------------------------------------------------------
If you decided to use the new 1.6 method from Step 3 and the only field present is the auth_session, then this is how you input the Access Token and the UUID.
token:${auth_access_token}:${auth_uuid}
Simple replace the ${auth_session} with this. Which in turn is replaced with the Access Token and UUID.

• ${version_name}

is replaced with the version you chose from the settings menu.

• ${game_directory}

is replaced with the directory for which you wish everything to be saved. This can select a different area to create a "safe" area of saving worlds related to a profile or mod packs.

• ${game_assets}

is replaced with the directory that contains all the files Minecraft uses for sound and etc.

• ${auth_uuid}

is replaced with the UUID obtained by the new 1.6 login process. This is an ID assigned to the player. Which should never change.

• ${auth_access_token}

is replaced with the access token that should have been saved on last login. This can be reassigned so long as this account wasn't logged in by another client that doesn't use the correct methods. For more information read the link in Step 3.

-------------------------

The mainClass is a parameter that is fed to java and is part of the command that is issued.

The list of "libraries" is all the files needed for Minecraft to run correctly.

You'll notice that some of the libraries have the key of "rules" on it. This section describes which OS can use what. So for example, if it says "allow" and has nothing under it, then every OS can download it. But, if it also says "disallow" then it has "os" right below and it lists a specific OS, then that OS cannot use that. I'm assuming that if it says "allow" and there happens to be some listed under the "os" there, then only those may use that file.

The ones that represent native files usually have the key "natives" associated with it. You'll download these, but you will not run directly from these.

Each of these library files are named in a unique way. To translate it to a usable form, you take the original of

"A.B.C.D:1:2"

and change it to

"A\B\C\D\1\2\1-2.jar"

Minecraft needs 4 things. Assets, Libraries, Natives, and the Jar.

The Assets are obtained by parsing the xml file at
https://s3.amazonaws...craft.Resources
and for each "Key", download it. Where it downloads each Key is relative to that xml file. An example would be
https://s3.amazonaws.../icon_16x16.png
These are saved usually in the assets folder.

C:\LOCATION\.minecraft\assets\icons\icon_16x16.png

Be aware that the Minecraft.Resources has multiple pages. In order to get the next page, place
?marker=Last\Key\Of\Previous\Page
at the end of
https://s3.amazonaws...craft.Resources
and you'll get the next page. You'll know that your on the last page when "isTruncated" is false.
---------------------------
The libraries are obtained by getting that list of "libraries" from earlier and doing the same thing as the assets. Except, we get all of them from
https://s3.amazonaws...load/libraries/
An example of that would be
https://s3.amazonaws...s-lang3-3.1.jar
These are saved usually in the libraries folder. Much like

C:\LOCATION\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar

---------------------------
While downloading the Natives from within the "libraries" list, you'll notice that under the "natives" key it lists strings associated with specific Operating Systems. You'll need the one your downloading for, in this case windows, and attach it to the end of the download strings. But right before the ".jar" on the link.
For example:
https://s3.amazonaws...ves-windows.jar

if ${arch} is at the end of any of these natives or libraries, then you'll need to replace that with 64 or 32. What ever type of CPU you may have. 64bit or 32bit.
---------------------------
The Jar is found very easily and is probably the easiest. As I have said before, it can be found right next to the json.
http://s3.amazonaws....nload/versions/VERSION/VERSION.jar
An example of that would be
http://s3.amazonaws....1.4.7/1.4.7.jar
This file is usually saved in the versions folder. Like

C:\LOCATION\.minecraft\versions\1.6.2\1.6.2.jar

The natives, the ones that have the key "natives" assigned to it back in #.#.#.json, are to be extracted/unzipped to a directory. The place everyone usually puts them is right next to the jar in the versions directory. In my launcher, I plan on having them extract to the folder "1.6.2-natives-AL74". The AL74 means nothing, other than the fact that my launcher created it.
So it should be at

C:\LOCATION\.minecraft\versions\1.6.2\1.6.2-natives-AL74\

Be sure to extract everything and exclude the "META-INF" folder.

Lets create the command line. So first we start by calling java. Java can be called with or without a CMD Prompt. Lets go without. ("java" is with a CMD Prompt")

javaw

Then we tell it how much ram to start with.

-Xms512m

Then lets tell it where to stop giving it ram.

-Xmx1024m

Now we need to tell it where we extracted the natives to.

-Djava.library.path=C:\LOCATION\.minecraft\versions\1.6.2\1.6.2-natives-AL74

Then Add the list of libraries to it. Remember! Only the libraries, do not add the natives to this list. Also! Be sure to add a ";" between each entry instead of a space. Its the separator.

-cp file;file;file;file;file;file;file;file

one of the files could be

C:\LOCATION\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar

Then attach the jar file to the end of the libraries with a ";" between them. Just remember not to end with the ";" or you might get an error.

;C:\LOCATION\.minecraft\versions\1.6.2\1.6.2.jar

Insert the parameter into the command Line "mainClass" which in this case represents

net.minecraft.client.main.Main

Finally, insert the arguments. Assuming, of course, that you already replaced all the data within the line. "minecraftArguments" which, at this point, would represent

--username TrinaryAtom --session 44324328965854839543 --version 1.6.2 --gameDir "C:\LOCATION\.minecraft" --assetsDir "C:\LOCATION\.minecraft\assets"

Or

--username TrinaryAtom --version 1.7.2 --gameDir "C:\LOCATION\.minecraft" --assetsDir "C:\LOCATION\.minecraft\assets" --uuid 2321dufh7892hfes79y --accessToken fdshg7843y78gsdf9fd

When done should look something like this;

javaw -Xms512m -Xmx1024m -Djava.library.path=C:\LOCATION\.minecraft\versions\1.6.2\1.6.2-natives-AL74 -cp C:\LOCATION\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;C:\LOCATION\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl\2.9.0\lwjgl-2.9.0.jar;C:\LOCATION\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.0\lwjgl_util-2.9.0.jar;C:\LOCATION\.minecraft\libraries\argo\argo\2.25_fixed\argo-2.25_fixed.jar;C:\LOCATION\.minecraft\libraries\org\bouncycastle\bcprov-jdk15on\1.47\bcprov-jdk15on-1.47.jar;C:\LOCATION\.minecraft\libraries\com\google\guava\guava\14.0\guava-14.0.jar;C:\LOCATION\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar;C:\LOCATION\.minecraft\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\LOCATION\.minecraft\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;C:\LOCATION\.minecraft\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;C:\LOCATION\.minecraft\libraries\com\google\code\gson\gson\2.2.2\gson-2.2.2.jar;C:\LOCATION\.minecraft\versions\1.6.2\1.6.2.jar net.minecraft.client.main.Main --username TrinaryAtom --session 44324328965854839543 --version 1.6.2 --gameDir C:\LOCATION\.minecraft --assetsDir C:\LOCATION\.minecraft\assets

Or with

--uuid 2321dufh7892hfes79y --accessToken fdshg7843y78gsdf9fd

This is what it would look like if I changed the spaces (that separates each parameter) into a new line.

javaw
-Xms512m
-Xmx1024m
-Djava.library.path=C:\LOCATION\.minecraft\versions\1.6.2\1.6.2-natives-AL74
-cp C:\LOCATION\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar;C:\LOCATION\.minecraft\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;C:\LOCATION\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl\2.9.0\lwjgl-2.9.0.jar;C:\LOCATION\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.0\lwjgl_util-2.9.0.jar;C:\LOCATION\.minecraft\libraries\argo\argo\2.25_fixed\argo-2.25_fixed.jar;C:\LOCATION\.minecraft\libraries\org\bouncycastle\bcprov-jdk15on\1.47\bcprov-jdk15on-1.47.jar;C:\LOCATION\.minecraft\libraries\com\google\guava\guava\14.0\guava-14.0.jar;C:\LOCATION\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar;C:\LOCATION\.minecraft\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\LOCATION\.minecraft\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;C:\LOCATION\.minecraft\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;C:\LOCATION\.minecraft\libraries\com\google\code\gson\gson\2.2.2\gson-2.2.2.jar;C:\LOCATION\.minecraft\versions\1.6.2\1.6.2.jar
net.minecraft.client.main.Main
--username TrinaryAtom
--session 44324328965854839543
--version 1.6.2
--gameDir C:\LOCATION\.minecraft
--assetsDir C:\LOCATION\.minecraft\assets

Or

--uuid 2321dufh7892hfes79y
--accessToken fdshg7843y78gsdf9fd