JaCoCo Console Reporter Maven Plugin

A custom Maven plugin that generates a textual tree-like coverage report from JaCoCo's execution data files, displaying coverage metrics (Class %, Method %, Branch %, Line %) for packages, source files, and the entire project.

Features

• Reads coverage data from jacoco.exec files
• Analyzes class files from the project's build output directory
• Outputs a hierarchical console-based report with coverage metrics
• Tree-like package structure visualization with collapsible paths
• Instant visibility of coverage metrics during build
• Multi-module project support with option to defer reporting until the end
• Automatic scanning for jacoco.exec files across modules
• Support for custom JaCoCo execution file patterns
• Combined weighted coverage score based on customizable weights
• Exclude target directory to ignore generated files

Prerequisites

• Maven 3.x
• JaCoCo plugin configured in your project to generate jacoco.exec

Installation

Add the plugin to your project's pom.xml:

<build>
    <plugins>
        <plugin>
            <groupId>io.github.svaningelgem</groupId>
            <artifactId>jacoco-console-reporter</artifactId>
            <version>1.0.0</version>
            <executions>
                <execution>
                    <goals>
                        <goal>report</goal>
                    </goals>
                    <phase>verify</phase>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Usage

Run the plugin after tests:

mvn verify

Ensure the JaCoCo plugin has executed beforehand to generate jacoco.exec.

Configuration

Parameter	Description	Default Value
jacocoExecFile	Path to the JaCoCo execution data file	${project.build.directory}/jacoco.exec
classesDirectory	Directory containing compiled classes	${project.build.outputDirectory}
deferReporting	Defer reporting until the end (for multi-module projects)	true
showFiles	Whether to show individual source files in the report	false
showTree	Whether to show the tree structure in the report	true
showSummary	Whether to show the summary information	true
scanModules	Automatically scan for exec files in project modules	false
baseDir	Base directory for module scanning	${project.basedir}
additionalExecFiles	Additional exec files to include in the report	[]
weightClassCoverage	Weight for class coverage in combined score	0.1
weightMethodCoverage	Weight for method coverage in combined score	0.1
weightBranchCoverage	Weight for branch coverage in combined score	0.4
weightLineCoverage	Weight for line coverage in combined score	0.4
ignoreFilesInBuildDirectory	Ignore autogenerated files in build directory	true

Default Output

[INFO] Overall Coverage Summary
[INFO] Package                                    │ Class, %         │ Method, %        │ Branch, %        │ Line, %
[INFO] --------------------------------------------------------------------------------------------------------------------------------------------------------
[INFO] com.example                                │ 100.00% (3/3)    │ 83.33% (5/6)     │ 50.00% (2/4)     │ 75.00% (15/20)
[INFO] ├─model                                    │ 100.00% (1/1)    │ 100.00% (2/2)    │ 50.00% (1/2)     │ 87.50% (7/8)
[INFO] └─util                                     │ 100.00% (1/1)    │ 100.00% (2/2)    │ 50.00% (1/2)     │ 87.50% (7/8)
[INFO] --------------------------------------------------------------------------------------------------------------------------------------------------------
[INFO] all classes                                │ 100.00% (3/3)    │ 83.33% (5/6)     │ 50.00% (2/4)     │ 75.00% (15/20)
[INFO] Overall Coverage Summary
[INFO] ------------------------
[INFO] Class coverage : 100.00% (3/3)
[INFO] Method coverage: 83.33% (5/6)
[INFO] Branch coverage: 50.00% (2/4)
[INFO] Line coverage  : 75.00% (15/20)
[INFO] Combined coverage: 68.33% (Class 10%, Method 10%, Branch 40%, Line 40%)

Output with all options on

[INFO] Overall Coverage Summary
[INFO] Package                                    │ Class, %         │ Method, %        │ Branch, %        │ Line, %
[INFO] --------------------------------------------------------------------------------------------------------------------------------------------------------
[INFO] com.example                                │ 100.00% (3/3)    │ 83.33% (5/6)     │ 50.00% (2/4)     │ 75.00% (15/20)
[INFO] ├─model                                    │ 100.00% (1/1)    │ 100.00% (2/2)    │ 50.00% (1/2)     │ 87.50% (7/8)
[INFO] │ └─Model.java                             │ 100.00% (1/1)    │ 100.00% (2/2)    │ 50.00% (1/2)     │ 87.50% (7/8)
[INFO] ├─util                                     │ 100.00% (1/1)    │ 100.00% (2/2)    │ 50.00% (1/2)     │ 87.50% (7/8)
[INFO] │ └─Util.java                              │ 100.00% (1/1)    │ 100.00% (2/2)    │ 50.00% (1/2)     │ 87.50% (7/8)
[INFO] └─Example.java                             │ 100.00% (1/1)    │ 33.33% (1/2)     │ 0.00% (0/0)      │ 25.00% (1/4)
[INFO] --------------------------------------------------------------------------------------------------------------------------------------------------------
[INFO] all classes                                │ 100.00% (3/3)    │ 83.33% (5/6)     │ 50.00% (2/4)     │ 75.00% (15/20)
[INFO] Overall Coverage Summary
[INFO] ------------------------
[INFO] Class coverage : 100.00% (3/3)
[INFO] Method coverage: 83.33% (5/6)
[INFO] Branch coverage: 50.00% (2/4)
[INFO] Line coverage  : 75.00% (15/20)
[INFO] Combined coverage: 68.33% (Class 10%, Method 10%, Branch 40%, Line 40%)

Advanced Usage

Multi-Module Projects

The plugin is configured by default to defer reporting until the end.

This will wait with generating the report until the last module in the build.

Custom JaCoCo File Locations

If your JaCoCo plugin uses a non-default location for the execution data file:

<plugin>
    <groupId>io.github.svaningelgem</groupId>
    <artifactId>jacoco-console-reporter</artifactId>
    <version>1.0.0</version>
    <configuration>
        <jacocoExecFile>${project.build.directory}/custom-jacoco.exec</jacocoExecFile>
    </configuration>
    <!-- ... -->
</plugin>

Customizing Report Output

You can configure which parts of the report are displayed:

<plugin>
    <groupId>io.github.svaningelgem</groupId>
    <artifactId>jacoco-console-reporter</artifactId>
    <version>1.0.0</version>
    <configuration>
        <!-- Show or hide the tree structure -->
        <showTree>true</showTree>
        <!-- Show or hide individual source files -->
        <showFiles>true</showFiles>
        <!-- Show or hide the summary information -->
        <showSummary>true</showSummary>
    </configuration>
    <!-- ... -->
</plugin>

Customizing Coverage Weights

You can adjust the weights used to calculate the combined coverage score:

<plugin>
    <groupId>io.github.svaningelgem</groupId>
    <artifactId>jacoco-console-reporter</artifactId>
    <version>1.0.0</version>
    <configuration>
        <weightClassCoverage>0.2</weightClassCoverage>
        <weightMethodCoverage>0.2</weightMethodCoverage>
        <weightBranchCoverage>0.3</weightBranchCoverage>
        <weightLineCoverage>0.3</weightLineCoverage>
    </configuration>
    <!-- ... -->
</plugin>

Excluding Files from Coverage

The plugin supports excluding specific files or packages from coverage reports. There are two ways to configure exclusions:

1. Using JaCoCo Exclusions: The plugin automatically respects exclusion patterns defined in your JaCoCo plugin configuration:

   <plugin>
       <groupId>org.jacoco</groupId>
       <artifactId>jacoco-maven-plugin</artifactId>
       <configuration>
           <excludes>
               <exclude>com/example/generated/**/*</exclude>
               <exclude>**/*Controller.class</exclude>
               <exclude>com/example/model/*</exclude>
           </excludes>
       </configuration>
   </plugin>

2. Automatically Exclude Build Directory Files: By default, the plugin will ignore files in the build directory, which are typically auto-generated. You can disable this with:

   <plugin>
       <groupId>io.github.svaningelgem</groupId>
       <artifactId>jacoco-console-reporter</artifactId>
       <configuration>
           <ignoreFilesInBuildDirectory>false</ignoreFilesInBuildDirectory>
       </configuration>
   </plugin>

Exclusion Pattern Syntax

The exclusion pattern for JaCoCo is:

• * matches any character except path separators
• ** matches any directory
• File paths use / as separator regardless of the operating system
• Patterns without the .class suffix will automatically match class files

For example:

• com/example/model/* - Excludes all files directly in the model package
• com/example/generated/**/* - Excludes all files in generated and its subpackages
• **/*Controller.class - Excludes all files ending with "Controller.class" in any package

Implementation Details

The plugin works by:

1. Detecting JaCoCo execution data files (default or custom locations)
2. Loading the execution data using JaCoCo's API
3. Analyzing compiled classes using the execution data
4. Building a hierarchical directory structure representing the package organization
5. Calculating coverage metrics (class, method, branch, line) for each node
6. Generating a tree-like report to the console
7. Computing a weighted combined coverage score
8. Applying exclusion patterns to filter out specific files or packages

Contributing

Contributions are welcome! Feel free to submit issues or pull requests to enhance this plugin.

Building from Source

mvn clean install

Running Tests

mvn test