JAR Analysis

Inspect your JAR before packaging to understand what's inside, find optimization opportunities, and catch potential issues.

Usage

# Analyze current project (builds uberjar first)
jbundle analyze

# Analyze a pre-built JAR directly
jbundle analyze --input ./target/app-standalone.jar

What It Reports

Category Breakdown

Every entry in the JAR is classified into one of:

Category	Matches
Classes	*.class
Clojure sources	*.clj, *.cljc, *.cljs
Java sources	*.java
Native libs	*.so, *.dylib, *.dll, *.jnilib
Metadata	META-INF/* (non-class)
Resources	Everything else

Top Packages

Entries are grouped by the first 3 path segments (matching Maven groupId convention). For example, org/apache/commons/lang3/StringUtils.class maps to org.apache.commons.

Clojure Namespaces

Detected from __init.class entries. For example, myapp/core__init.class maps to namespace myapp.core.

Shrink Estimate

Shows how much space --shrink would save by removing non-essential files (Maven metadata, JAR signatures, Java source files, build tool artifacts).

Potential Issues

• Duplicate classes — Same class path appearing multiple times (common in uberjars with dependency conflicts)

• Large resources — Files over 1 MB that may be worth reviewing (embedded models, datasets, etc.)

Example Output

JAR: target/app-standalone.jar (87.3 MB)
Entries: 12,345

Category              Size       %    Files
────────────────────────────────────────────────
Classes           42.1 MB    48%    8,432
Resources         38.7 MB    44%    1,203
Native libs        5.2 MB     6%       12
Metadata           1.3 MB     2%      806

Top packages by size:
  org.apache.poi                       28.4 MB  1,322 files
  com.google.guava                      3.1 MB    456 files
  org.clojure                           2.8 MB    342 files

Clojure namespaces:
  clojure.core                          2.1 MB    342 files
  myapp.handlers                        0.5 MB     28 files

Estimated --shrink savings: 12.4 MB (14%) — 892 removable files

Potential issues:
  Duplicate class: javax/servlet/Servlet.class (3 occurrences)
  Large resource: data/model.bin (8.5 MB)

When to Use

• Before first build — Understand your JAR composition and spot bloat

• Evaluating --shrink — See the savings estimate before enabling it

• Debugging binary size — Find which dependencies are largest

• Dependency conflicts — Detect duplicate classes from overlapping dependencies