JavaInspect - Utility to visualize java software

Table of Contents

1. Overview

JavaInspect utility simplifies understanding the computer program code by automatically visualizing its structure.

See example produced graphs for Sixth 3D - 3D engine project.

JavaInspect can be used as a standalone commandline utility as well as java library. JavaInspect uses primarily Java built-in reflection to discover and visualize any part of Java program.

JavaInspect currently has no graphical user interface, configuration files, embedded scripting support, direct Maven, Gradle or Ant integration. See usage to learn how to instuct Javainspect what to do.

After discovering application structure and optionally filtering out unimportant parts, JavaInspect produces GraphViz dot file that describes data to be visualized. Then launches GraphViz to generate bitmap graph in PNG or SVG format.

Notes:

  • JavaInspect is developed and tested so far only on GNU/Linux.

A very simple example:

example-thumbnail.png

Graph legend: legend.png

2. Installation

GraphViz - shall be installed on the computer.

On Ubuntu/Debian GraphViz can be installed using: 

sudo apt-get install graphviz

To use JavaInspect via Java API, no further installation is needed. JavaInspect will be embedded into your project as dependency. This is described in usage via Java API. It will expect GraphViz to be available in the system.

To use JavaInspect as a commandline tool, JavaInspect source repository has to be cloned locally. See: Getting the source code.

Then study and execute installation script: 

cd commandline\ launcher
./install

After installation, new commandline tool should be available 

javainspect

Quick commandline usage help can be viewed by issuing 

javainspect --help

3. Usage

JavaInspect utility can be used in 2 different ways:

3.1. Usage via Java API

Requires that classes to be visualised are available in the classpath.

To get JavaInspect into same classpath with your projecs I so far came up with 2 solutions:

  1. Add JavaInspect library in your project as a dependency.
  2. Create new Java project for the purpose visualizing your other projects and include JavaInspect and your projecs binary artifacts (Jar's) into new project classpath. Built binary Jar's (with no source code) are sufficient because JavaInspect operates via reflection.

Simple Java based control/configuration code needs to be written for each project. I usually put such code into directories devoted for JUnit tests. Because it needs not to be compiled/embedded into final product or project artifact I'm just willing to visualize.

Control code in general does the following:

  1. Create graph object.
  2. Java reflection/classloaders does not provide mechanism for discovering all classes under given package. Therefore you need to declare at least some classes to be added to the graph by manually adding individual classes to the graph. For every class added to the graph, GraphViz will recursively inspect it and add all referecned classes to the graph as well.
  3. Graphs easilly get very big and complex so optionally we filter important code using classname glob patterns based blacklist and/or whitelist.
  4. Optionally we can tune some rendering parameters like:
    • Possibility to remove orphaned classes (classes with no references) from the graph.
    • Specify target directory for generated visualization files. (Default is current directory)
    • Keep intermediate GraphViz dot file for later inspection.
  5. Render graph.

3.1.1. Example 1: individually picked objects

This example demonstrates generating of class graph from hand picked classes and visualizing GraphViz itself. 

// Create graph
final ClassGraph graph = new ClassGraph();

// Add some random object to the graph. GraphViz will detect Class from
// the object.
graph.add(graph);

// Also add some random class to the graph.
graph.add(Utils.class);

// Keep intermediary GraphViz DOT file for reference.
graph.setKeepDotFile(true);

// Produce bitmap image titled "JavaInspect.png" to the user Desktop
// directory
graph.generateGraph("JavaInspect");

Note: if desired, more compact version of the above: 

new ClassGraph().add(randomObject, RandomClass.class)
                .setKeepDotFile(true).generateGraph("JavaInspect");

Result:

3.1.2. Example 2: GraphViz embedded in another project

  1. Download project Sixth code snapshot.
  2. Inspect and run DataGraph.java.

3.1.3. Embedding JavaInspect in your Maven project

Declare JavaInspect as dependency: 

<dependencies>
    ...
    <dependency>
        <groupId>eu.svjatoslav</groupId>
        <artifactId>javainspect</artifactId>
        <version>1.7</version>
    </dependency>
    ...
</dependencies>

Add Maven repository to retrieve artifact from: 

<repositories>
    ...
    <repository>
        <id>svjatoslav.eu</id>
        <name>Svjatoslav repository</name>
        <url>https://www3.svjatoslav.eu/maven/</url>
    </repository>
    ...
</repositories>

4. TO DO

Note: Because this is side project (and I have many of them) I can only contribute few hours per year at average. Any help is welcome. A LOT of cool ideas could be implemented. For intstance:

  • BUG: Should not hide references if there are too many of them to classes if referring classes are not visible anyway because of blacklist/whitelist rules. Basically reference counting should exclude not visible classes.
  • BUG: Orphaned class removal does not work always. There are many bugs and corner cases to find and fix still.
  • BUG: Code is not very readable. Document and refactor for better maintainability.
  • FEATURE: Create installable DEB package.
    • Submit it to some Debian developer for integration or become Debian package maintainer.
  • FEATURE: Make it modular. That is: central part, an application model could be standalone and serializable.
    • There could be multiple ways to acquire model:
      • By introspecting application via Java reflections (current mode of operation).
      • By parsing java source. (unfinished)
    • There could be ways to manipulate model:
      • Store/load/compare.
      • Trim uninteresting parts.
      • Highlight important parts.
    • There could be multiple ways to render model:
      • PNG/SVG (currently implemented)
      • PlantUML (TODO)
      • Interactive 3D visualization (TODO)
  • FEATURE: Implement (or integrate existing java parser https://javaparser.org/) to be able to produce code visualizations based on source code (in addition to current reflection based approach).
  • FEATURE: Integarte with PlantUML.
  • FEATURE: Add dark theme for generated graphs.
  • FEATURE: Sort Class fields by alphabet.
  • FEATURE: Visualize also concrete field values so it could be used as ultra cool runtime logging/debugging framework.
  • FEATURE: Possibility to visualize structure and data from JVM snapshot.
  • FEATURE: Possibility to attach to remote process to visualize data/structure using JVM debug port and mechanism.
  • FEATURE: Possibility to attach to JVM using JVM agent.
  • FEATURE: Possibility to inspect graphs in 3D using Sixth 3D engine.
  • FEATURE: Possibility to select classes/fields/values to be visualized in some graph query language. For greater flexibility in comparison to currently supported glob syntax.
  • FEATURE: Add option to control JavaInspect via JSON or XML config file. For example different graphs for given project could be defined once in plain text config, possibly with the aid of some interactive utility. Then defined graphs could be updated as part of project build or release process.
  • FEATURE: Configurable maven plugin to generate graphs as part of the project build/release process.

5. See also

Similar or alternative solutions:

6. Getting the source code

Program authors:

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Source code:

Created: 2024-12-11 ke 09:12

Validate