Java power tools series - Diagramming and Reverse Engineering Tools

I hope, you have already read "Preface" of my java power tools series. This post summarizes some of tools for drawing manual diagrams as well as generating diagrams from existing java codebase.

This post would benefit you, if your answer is "No" for below questions

• UML diagrams are widely used for software architecture and design documentation. Are you aware about UML tools, which offer forward engineering, reverse engineering or roundtrip engineering?
• Forward engineering = First design using UML diagrams and then generate code from diagrams.
• Reverse engineering = Generating diagram from code by using static and/or runtime approach.
• Roundtrip engineering =  Forward + Reverse engineering. UML diagram and Java code are constantly maintained in sync.

• There is a need to maintain large and complex legacy systems of the enterprise, but system’s documentation is missing or outdated. Beside that you have insufficient knowledge of functionality, architecture and code. In such situation do you use range of tools for visually explore the code or  doing impact analysis?

• You are not able to understand code sequence flow for the given functional use case of application. Do you know how tools can help to explore code of critical use cases by generating sequence diagrams on the fly? Well, runtime reverse engineering tools can expedite you to perform impact analysis of unknown code, and reduce the bug fix and release cycle time of applications.

My Favorite Tools

Following are some of my favorite tools, which evidently supported me while working on tasks like software architecture and design documentation, impact analysis during maintenance phase, java legacy systems assessment, etc. So I though to summarize those in this post along with few demo diagrams generated for Spring Petclinic application using different tools.

Diagramming Tools

Microsoft Visio - Though commercial, it is my most favorite tool to draw software architecture and design diagrams manually. Also you can empower it further by adding stencils like UML stencils, AWS stencils…

Alternatively sometimes I use free online web interfaces like,

• http://cacoo.com/ - to create a variety of diagrams such as site maps, wire frames, UML and network charts

• http://www.gliffy.com/ - to create professional-quality flowcharts, diagrams, floor plans, technical drawings, and more

• http://www.websequencediagrams.com/ - to draw sequence diagrams

Static Reverse Engineering Tools

This means, such tools would allow you to generate diagrams from the source code without running your application.

ObjectAid (Free for class diagram / Commercial for sequence diagrams)

• It is a lightweight code visualization tool for the Eclipse IDE. The great features is that, it can show Java source code and libraries in live UML class and sequence diagrams that automatically update as code changes.
• My personal feedback: Easy to use. I found it highly useful to maintain critical class and sequence diagrams of software system up-to-date as the code changes.

Architexa (Individual Edition is Free for 3 users for a year / Purchase Commercial Edition)

• One can use it by only installing Architexa plugin in Eclipse IDE.
• Features - Generate diagrams from code, Understand and document code from diagrams, Share and collaborate visually.

• Supported diagrams - Layered diagram, class diagram, sequence diagram.
• My personal feedback: Easy to use. Initially it takes few minutes to build indexes based on the size of the project source code, but then offers to generate excellent diagrams from the java code and specifically I love the unique layered diagrams it can generate.

ModelGoon (Free)

• Eclipse plugin to generate package, class, interaction and sequence diagrams from existing java source code
• My personal feedback: Doesn't generate beautiful diagrams, but may be helpful to generate simple diagrams for some portion of java code.

Runtime Reverse Engineering Tools

Such tools demand your application to run, so first of all you need to setup runtime environment of the application. Then run a functional use case scenario and record corresponding trace using options (e.g. start and stop recording) given in the tool. That would generate sequence or class or package diagram for the given call trace, which can expedite developer to analyze application code of that functional use case scenario from generated diagram in just few minutes. All in all, such tool are extremely helpful when developers need to discover and document unknown codebase for the given functional use case scenarios.

Flow Visual Tracer / FindTheFlow

• Features - (1) Flow allows you to visualise the dynamic dependencies between packages, types and methods. (2) Flow provides a view of method call progression of all threads for better understanding of the execution paths. Flow records the entire execution so that it can be replayed forward but also back in time, and as many times as needed.

• My personal feedback: It's indeed easy-to-getting-started and generates nice package/class/method level visual diagrams. The tool has remarkable ability to enable us recording the execution of code flow for the given use case, and then it can be replayed and visualized through a web interface. Be aware, the tool is free at this stage and it is likely that free version will be always offered in future (as per FAQ). However, you never know. So I suggest check its license, before using it.

Maintainj (7 days Evaluation, then Commercial)

• Maintainj claims - Generate interactive sequence diagram and captures basic context information from call trace by running a use case, which helps to reduce the bug fix and release cycle time of applications; and document code in minutes.
• Three step process - (1) Instrument code (2) Generate trace files (3) View diagrams (you need Eclipse IDE to install Maintainj plugin for analysis of generated sequence and class diagrams)
• Supports - (1) JRE 1.4, 1.5, 1.6 and 1.7. (2) Swing, Applets, JUnit (3) Most of widely used J2EE application servers and Databases
• My personal feedback: Personally I found it quite useful for runtime reverse engineering. But you must be aware that, it has performance penalty to increase server startup time. So should only use in development/qa environment, but not in production.

EclipseJIVE or EclipseDiver 

• Both are Free Eclipse plugins and has runtime reverse engineering ability to generate sequence diagrams from java source code

• My personal feedback: Based on my personal experience, I am skeptical about stability of both compare to Maintainj. Also Maintainj has more advance features compare to both.
• Eclipse Diver - The last release is in Sep-2012, so it doesn't look active anymore. Also there is major stability issue open for Windows 7 for runtime sequence diagrams generation and analysis, which is mentioned as not going to be fixed in near future. Still one may try it in Linux or other than Windows 7 OS. 
• Eclipse JIVE - When I tried it for one of J2EE application, it has taken more than 10 minutes time to start server and then also eclipse was getting hang sometimes. I tried with Eclipse Kepler only, and did not check with another Eclipse version!  

Forward and Roundtrip Engineering Tools

Modelio (Free) / ModelioSoftJava Solution (Commercial)

• Modelio is an open source modeling environment (UML2, BPMN2, ...). By installing Java Designer Module (Free), it supports forward and roundtrip engineering. This module claims to support Java 7 too. Some of other Free Modules for Modelio are - Pattern Designer, Hibernate Designer, WSDL Designer, XSD Designer, etc. See reverse engineering using Modelio in action video.
• My personal feedback: Modelio claims that reverse engineering feature is also supported in Java Designer Module Free. But when I installed Java Designer Module, I could not find such reverse engineering option in the Modelio as given in the available documentation and hence could not evaluate "Reverse Engineering" feature. I am not sure, if the reverse engineering related documentation is applicable to the commercial edition of ModelioSoft! Anyway personally I prefer to use Modelio forward and roundtrip engineering features only for POC/R&D purpose, but not for complex software or enterprise application development.

Miscellaneous Tools

Dr. Garbage Tools (Free Eclipse Plugin)

• Source code visualizer, specifically can be useful to review and analyze complex conditional logic flow within particular method of java class.

Below are miscellaneous tools, which I consider sometimes for generating diagrams from java code to represent internal and external dependencies of software components.

Jar2UMLfor representing dependencies as diagram  (Free Eclipse Plugin)

CodeproAnalytix for Dependency Graph Analysis (Free Eclipse Plugin)

SonarQubefor Dependency Structure Matrix (Free)

JArchitect for Interactive diagrams (Commercial)

Final Thoughts

• Use applicable tools to generate diagrams from java code & accelerate productivity to understand/analyze the code.
• Keep software architecture and design documents up-to-date by adoption of appropriate tools.

Updates History

• 28/Dec/2014 - Added JArchitect in Miscellaneous tools section
• 19/Jun/2016 - Added Flow tool (as per comment of Yiquan Zhou) in runtime reverse engineering tools section.

Disclaimer

I am not biased to particular free or commercial tools, rather my objective is about sharing my own experience on set of tools.

If you know or have experienced any other reverse engineering tools suitable for Java projects analysis, please share the name of such tool along with your personal feedback in the comment.