Installer

Double-click/execute it for a window. Run it with arguments for command-line interaction.

java -jar installer.jar                      # Graphical installer
java -jar installer.jar client               # Add a profile to the Minecraft launcher
java -jar installer.jar server -d ./server   # Set up a dedicated server
java -jar installer.jar mmc                  # Create a Prism/PolyMC/MultiMC instance
java -jar installer.jar --help

Exit Codes

Code	Meaning
0	Success
1	Internal error
2	Usage error
3	Network failure
4	A download failed its size or SHA-1 check
5	The install directory is unusable
6	No suitable Java was found or could be fetched
7	Cancelled

JSON Output

--json prints one JSON object per line on standard output. Log lines go to standard error.

Event	Fields	Printed
stage	name	When a phase starts
progress	stage, detail, done, total	During a phase, total -1 if unknown
versions	versions	By list-versions, newest first
plan	target, version, root, actions, notes	By --dry-run, in place of result
result	ok true, root, files, notes	After a successful run
result	ok false, code, message	After a failed run, code is the exit code

Cache

Everything the installer keeps lives in ~/.cleanroom. Set -Dcleanroom.homeDir=<path> to move it.

Path	Contains
installer/installers/	Downloaded Cleanroom installer jars
installer/packs/	Downloaded MultiMC packs
installer/versions.txt	The version list, refreshed after an hour
installer/logs/	Run logs
java/	Java runtimes fetched by --provision-java

--dry-run still downloads the installer jar into the cache, because the plan is read from it.

Install Profile

An installer jar carries install_profile.json. Spec 1 keeps every spec 0 key and adds the ones below. A profile without them gets the defaults.

Key	Type	Meaning
spec	number	1
cleanroomVersion	string	Cleanroom version, derived from path when absent
java.minimum	number	Lowest Java feature version accepted, default 25
java.maximum	number	Highest Java feature version accepted, default 25
java.recommended	number	Version to look for first and to provision, default 25
java.distro	string	Preferred vendor when provisioning, default zulu
jvmArgs	string[]	Default JVM arguments for the launcher profile
serverMainClass	string	Server main class, default is the one in version.json
serverTweakers	string[]	Server tweak classes, default is the built-in list

The installer does not read mainClass, tweakers, serverJarPath and repositories yet.

Layout

Module	Contains
core	Profiles, downloads, targets, Java resolution, directory detection
ui	The installer's window and its Swing look and feel
app	Entry point, the command line, and the shaded jar.

Adding a Mode

• Implement a new InstallTarget and add to core/src/main/resources/META-INF/services/com.cleanroommc.installer.target.InstallTarget.

Compatibility

• Two paths inside an installer jar are load-bearing and must not move: /version.json and /maven/com/cleanroommc/cleanroom/<version>/cleanroom-<version>-universal.jar.
  • CleanroomRelauncher reads both directly out of published installer jars.
• version.json is written self-contained, with no inheritsFrom.
• Inheriting from 1.12.2 would cause the launcher to merge parent libraries which ends up adding LWJGL 2 onto the classpath. (Previous installer/zip did this.)