Below is the list of best free Eclipse plug-ins for a developer to be more productive -
Code Quality Plugins
FindBugs plug-in is used with eclipse IDE and it is the software used to find bugs in Java programs. It’s free software licensed under Lesser GNU Public License. This is one of the most popular eclipse plugins and also available on Maven, Netbeans and IntelliJ.
Checkstyle plug-ins can be integrated to IDE Eclipse and it ensures the Java code follows the coding standards.
ECLemma is a free tool available through Eclipse Public License and it provides fast development and test cycles. You can use “launch” in the code coverage mode which works like actual run/debug mode. One can render the analysis of the code through coverage view, source highlighting, counters and sessions.
JDepend4Eclipse helps to traverse file directories and assists in measuring the quality of design. It is an open source tool licensed under Eclipse Public License v1.0.
PMD is a source code analyzer which helps to detect used variables and bad codes. (Update URL - http://pmd.sourceforge.net/eclipse/)
SourceHelper helps to code and debug, and it also aids in providing clarity to the written code.
Structure101 helps to influence architecture when the code is edited, which means you can change the architecture without disrupting the code.
Text Editor Plugins
The plug-in helps to add new editor to output consoles, toolbar, and it also help to import and export data. It is licensed under Eclipse Public License v1.0.
Eclim helps to bring Eclipse functionality to one of the best editors - Vim, wherein development can be done in various languages and it also provides bug fixing provisions. It is released under GPLV3.
Eclipse-rbe is used for editing Java resources and its features include warnings for missing values, sorted keys, conversion from/to Unicode etc. It is licensed under GNU library or LGPL.
Apache IvyDE is an Eclipse plug-in which helps to integrate Apache Ivy’s feature of dependency management to Eclipse. Additionally, it helps to manage dependencies in ‘ivy.xml’. It can be used with plug-in WTP and Ant.
M2eclipse helps to manage both simple and multi module projects, and Maven integration for Eclipse (M2eclipise) helps to launch maven from Eclipse. It provides features such as dependency management and automatic downloading. You may also want to checkout Some Best Free Maven Plug-ins for Developers
Version Control Integration Plugins
Subclipse is a SVN plug-in which offers support for subversion of Eclipse IDE and it is licensed under EPL 1.0. Subeclipse 1.6.x supports ColabNet Merge Client. Subclipse provides easy interface to use the features.
EGit plug-in provides support, synchronizes view, reading for .git/ exclude files, provides rebasing and has streamlined commands for pulling and pushing.
MercurialEclipse is one of the active Version Control System which gives you access on registration. It is a reliable plug-in which provides cloning repositories, push-pull synchronization and enables easy rollback.
P4Eclipse seamlessly integrates the strengths of Perforce's version management system with Eclipse's. P4Eclipse provides a developer-oriented set of features from within the Eclipse Team framework that support a wide range of Agile and traditional development workflows.
Spring Tool Suite provides development environment and tools such as XML file wizards and graphical spring configuration editor, which can be used for easy development.
Spring IDE helps in developing Spring Application and provides interface to use the graphical editing framework. What’s more, Spring IDE display graphs of relationships and beans using configuration files. (Update site - http://springide.org/updatesite
Hibernator helps to create or update schema, run hibernate queries and create mapping documents. The user can synchronize a Java class to a related mapped file.
JbossTools 3.2x support JBoss, Hibernate, Drools, XHTML, Seam etc. (Update site - http://download.jboss.org/jbosstools/updates/JBossTools-2.1.2.GA)
Continuous Integration Related Plugins
Hudson Status is a simple plug-in that displays the status (red/green) of a application on Hudson build server. Hudson is a very powerful continuous integration server, that is used in many large software development projects.
Sonar Plug-in for Eclipse provides powerful integration of Sonar with Eclipse. It highlights code quality problems as we browse the code. Since the code quality standards definition is centralized on Sonar server, it ensures all developers are following same quality standards. Sonar is a open source platform used for centrally controlling the source code quality of software projects.
Other Utility Plugins
ASM Bytecode Outline plugin shows disassembled bytecode of current Java editor or class file, allows bytecode compare for Java/class files and shows ASMifier code for current bytecode. You can install ASM from Eclipse Update Manager. It allows bytecode comparison to Java class. (Update site - http://download.forge.objectweb.org/eclipse-update/)
Mylyn has a task focused interface and it provides a task management tool to the developers. Moreover, it helps to integrate rich editing tools and monitor activities.
Eclipse launcher is written in Delphi 6 and it helps to launch Eclipse IDE with configuration.
FileSync is licensed under Eclipse Public License v1.0 and it is a file synchronization tool used for creating, deleting and mapping files.
Log4E helps to use logger easily without getting bound to a special logging framework. Also, you can define your own preferences for logging templates.
All in all, plug-ins allows Eclipse to be coded in other languages. Eclipse plug-ins is indispensable nowadays, since it greatly streamlines Java applications and reduces the complexity of Java. However, installing too many plug-ins can slow down Eclipse. Hence you require selecting the plug-ins judiciously. There are a number of other productivity plug-ins too, besides the ones mentioned. Checkstyle, JBoss Tools and Jadclipse are three of them. Do let us know if you have used some other plug-ins which you were impressed with.