Machete

Machete is a gradle plugin that attempts to optimize the size of output JARs through both individual file optimizations and overall compression increases inspired by the Detonater project.

Simply applying the plugin should be enough to apply any optimizations in a standard environment, as it will collect output JARs that are known to be usable artifacts and optimize them after the build task.

Please note that this plugin works best on high-resource density projects. Code-heavy ones will have minimal success and may even inflate overall.

Optimizations

• JSON files are minimized by reading+writing through a custom formatter, which strips any whitespace.
• PNG files are run through the Oxipng project on maximum compression and metadata removal
• Nested JAR files are unpacked and have the same optimizations run on them
• XML files have extra whitespace removed
• The final result is then compressed with DEFLATE level 9, providing modest overall compression (bytecode doesn't compress well unfortunately)

There are also some disabled-by-default optimizations as they are technically lossy on the behavior of the jar.

• Local Variable Table stripping, disabled because this table is used for the "helpful NPEs" feature in java 14+
• Source file stripping, disabled because this is used to give the file a class was compiled from in error messages

More optimizations are planned as well, feel free to open an issue!

Installation

Machete is available on the gradle plugin portal under io.github.p03w.machete, simply apply the plugin to your project, and it should work out of the box.

See here for in-depth install instructions.

Configuration

To configure the plugin, use the machete block. This allows you to

• Add or remove tasks to pull output JARs from (additionalTasks/ignoredTasks, also please consider opening a PR if you use these)
• Disable overwriting the original artifacts (keepOriginal)
• Enable or disable specific optimizations (optimizations)

An example full config may look like:

machete {
    // Also optimize the output of task "foo"
    additionalTasks.add("foo")
    // Do not optimize the output of "bar"
    ignoredTasks.add("bar")
    
    // Keep the original copies in the build directory
    keepOriginal = true
    
    // Disable task hooking (if you want to manage it manually or seperately)
    finalizeAfter = ""
    
    // Disable the JIJ, PNG, and JSON optimizations
    jij.enabled = false
    png.enabled = false
    json.enabled = false
    
    // Enable all lossy optimizations
    lvtStriping.enabled = true
    sourceFileStriping.enabled = true
    
    // Make the PNG optimization (even though disabled here, shush)
    // Use less optimization and no alpha optimizations
    png.alpha = false
    png.optimizationLevel = 2
}

To locate tasks that can be added, use the dumpTasksWithOutputJars task, that will automatically list any tasks with output JARs.

Supported 3rd party plugins

This is a list of currently supported 3rd party plugins that Machete can automatically optimize the output of. Please see KnownGoodTasks.kt for this support. If you are using a plugin that doesn't specify its output artifacts, I'm sorry, but I can't add support, please consider poking the developer about using that system (although im sure the code here is garbage as well LMAO, gradle have good docs challenge (impossible)).

• shadow
• fabric-loom and most derivatives

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Notes on 2.0.0 for end users

• Optimization tasks now hook after assemble rather than the task that they're optimizing the output of, this is the most likely to break things but I believe it should be fine for most usecases
• Hooking on assemble can be changed or disabled if you want better control
• If using keepOriginal, the output will now be cached
  • Gradle managed this previously, but this makes the caching explicit
• Oxipng is de-duplicated now