Critical tools that every Java Developer should have in his toolbelt?

Question

I was trying to compile a list of tools that a good Java Developer should be know of, and keep in his Developer Tool Belt

I can think of a few

• Eclipse Development Environment - There are other IDEs, but you should know how Eclipse of eclipse.
• JUnit - Java Unit Testing Framework. Of course there are others, but...
• ANT
• Maven
• Soap UI - for testing SOAP endpoints
• jrat - Java Profiler. I don't know of other good Java profilers
• Java Decompiler - For when you just have to know what's in the jar file

Answer 1

• findbugs http://findbugs.sourceforge.net/
• hudson http://hudson-ci.org/

understanding of all major version control systems like:

• perforce
• cvs
• svn
• git
• etc.

and of course the jdk!

Answer 2

• VisualVM - for low level memory profiling
• Eclipse MAT - for high level memory profiling
• JMeter - for performance testing
• Mockito, EasyMock, PowerMock - for mocking
• FindBugs, Checkstyle, PMD - for static code analysis

Answer 3

• Hudson, near the top of the list.
• visualVM - good enough for most profiling needs (and I've heard of a number of Java profilers, but never of jrat)
• Cobertura or Emma for code coverage

Answer 4

• Continuous integration server: CruiseControl, Hudson, etc.
• Dependency injection: Google Guice, Spring, PicoContainer
• Slf4J: Simple Logging Facade for Java
• Mockito: Mocking Library
• Not Java specific but nonetheless essential: a good distributed source control (Git or Mercurial)

Answer 5

Critical

• Clean text editor ( Textmate, gVim )
• JDK ( java, javac, javap etc. )
• A webbrowser to read the javadocs

Non-critical

All those you mention but s/Eclipse/IntelliJ Idea/g

Answer 6

The Really Big Index: A list of all content pages in the The Java^TM Tutorial, because you can't know everything.