Goals

All Maven plugin goals — index, decompile, instrument, process, enhance, clean.

index

Build lightweight manifests for dependency jars. Creates one manifest per jar in .jackknife/manifest/ — just class names and resource paths, no ASM, no decompilation. Sub-second for an entire classpath.

Parameters

Details

• Resolution scope: TEST — sees compile, runtime, provided, and test dependencies
• Can be bound to the initialize phase for automatic indexing
• SNAPSHOT jars are re-indexed when the jar is newer than the manifest
• Generates .jackknife/USAGE.md with full instructions on each run

Examples

# Index project dependencies
mvn jackknife:index

# Find a class in ~/.m2/repository
mvn jackknife:index -Dclass=com.fasterxml.jackson.databind.ObjectMapper

# Broad search across all cached jars
mvn jackknife:index -Dscope=repo -Dfilter="**jackson**"

decompile

Decompile a class from an indexed jar using Vineflower. Decompiles the entire jar on first request — every class becomes a .java file in .jackknife/source/. Subsequent reads are direct file access.

Parameters

Details

• Aggregator: yes — runs once at the reactor root
• Resolution scope: TEST
• Searches manifests first, falls back to project artifacts
• Output goes to .jackknife/source/<groupId>/<artifact>/

Examples

mvn jackknife:decompile -Dclass=com.fasterxml.jackson.databind.ObjectMapper
mvn jackknife:decompile -Dclass=org.junit.Assert

instrument

Create instrumentation config for methods or classes. Searches manifests to find which jar contains the target, then writes config files to .jackknife/instrument/.

Parameters

Details

• Aggregator: yes — runs once at the reactor root
• If no -Dmethod, instruments all methods of the class
• Glob patterns: * matches one package level, ** matches any depth
• Also checks src/main/java/ and src/test/java/ for project classes

Examples

# One specific method
mvn jackknife:instrument -Dclass=org.tomitribe.util.Join -Dmethod=join

# One method with exact signature
mvn jackknife:instrument -Dclass=org.tomitribe.util.Join -Dmethod="join(String,Collection)"

# All overloads of a method
mvn jackknife:instrument -Dclass=org.junit.Assert -Dmethod=assertEquals

# All methods of a class
mvn jackknife:instrument -Dclass=org.tomitribe.util.Join

# Wildcard — all classes matching a pattern
mvn jackknife:instrument -Dclass="org.junit.**" -Dmethod=assertEquals

# All Handler classes
mvn jackknife:instrument -Dclass="**Handler"

# Timing mode — elapsed time and status only, no args or return values
mvn jackknife:instrument -Dclass=com.example.Foo -Dmethod=bar -Dmode=timing

process

Apply instrumentation to dependency jars. Reads config from .jackknife/instrument/, transforms matching classes with bytecode enhancement, writes patched jars to .jackknife/modified/, and swaps them into the Maven classpath via Artifact.setFile().

Details

• Lifecycle phase: initialize — runs before compilation
• Non-aggregator: runs per-module
• Resolution scope: TEST
• Automatic — no user invocation needed when bound in pom.xml

enhance

Apply instrumentation to project code. Reads config from .jackknife/instrument/_project/ and modifies compiled .class files in target/classes/ and target/test-classes/ in place. Writes META-INF/jackknife/handlers.properties for runtime auto-discovery.

Details

• Lifecycle phase: process-test-classes — runs after test compilation
• Modifies target/classes/ and target/test-classes/ directly
• Automatic — no user invocation needed when bound in pom.xml

clean

Remove .jackknife/ or a sub-path within it.

Parameters

Details

• Path validation: rejects .., absolute paths, and : characters
• Resolved path is verified to stay within .jackknife/

Examples

# Remove everything
mvn jackknife:clean

# Stop instrumentation (remove modified jars)
mvn jackknife:clean -Dpath=modified

# Clear decompile cache
mvn jackknife:clean -Dpath=source

# Remove a specific groupId's modifications
mvn jackknife:clean -Dpath=modified/org.tomitribe