Editing Java Edition Classic level format (section)

== File Format ==

===First Format===
{| class="wikitable sortable"
! Data
! Length (Bytes)
! Description
|-
| Block Array
| 4194304 (2^22)
| An array of blocks in the world in the order: layers of the world from y = 0 to build height, in each layer have strips from z = 0 to the edge of the world, in each strip have blocks from x = 0 to the edge of the world. Each byte represents a single block using [[Java Edition data values/Classic|their ID]].
|}

===Second Format===
{| class="wikitable sortable"
! Data
! Length (Bytes)
! Description
|-
| Magic Number
| 4
| A number used to identify the file. Always will be <code>27 1B B7 88</code>.
|-
| Version
| 1
| A version identifier byte <code>01</code>.
|-
| World Name
| Variable
| First two bytes will be a short for the length of the string then that length bytes will be ASCII characters for the string. This string will always be either "A Nice World" or "--" depending on the start version.
|-
| Creator Player Name
| Variable
| First two bytes will be a short for the length of the string then that length bytes will be ASCII characters for the string. In Classic 0.0.13a-dev this will always be "noname" but Classic 0.0.13a_03 will be the actual user's name.
|-
| Time Created
| 8
| A long value for the time the level was created in the Unix epoch.
|-
| Width
| 2
| The width of the world (x direction).
|-
| Height
| 2
| The height of the world (z direction).
|-
| Depth
| 2
| The depth of the world (y direction).
|-
| Block Array
| 4194304 (2^22)
| An array of blocks in the world in the following order: layers of the world from y = 0 to build height, in each layer have strips from z = 0 to the edge of the world, in each strip have blocks from x = 0 to the edge of the world. Each byte represents a single block using [[Java Edition data values/Classic|their ID]].
|}

===Third Format===
{| border="1" class="wikitable" data-description="File format"
! Position
! Size (bytes)
! Name
! Description
|-
| 0
| 4
| Magic ID
| A magic ID is a constant number used to identify the Minecraft file format. The current value is '''0x271bb788'''.
|-
| 4
| 1
| Version Number
| The version number represents the current format used to save the level. The current value is '''2'''.
|-
| 5
| Variable
| Serialized Java ''com.mojang.minecraft.level.Level'' Class
| More information about the serialization format used by Java is available in the [http://java.sun.com/developer/technicalArticles/Programming/serialization/ manual], however, the easiest way to edit the file is to use the [[Development resources/Example Minecraft Classic Level Editing Class|classes]] provided here with the official <span class="plainlinks">[http://minecraft.net/servers.jsp minecraft-server.jar file]</span>.
|}