What are Some Essential Java Libraries?

rleclerc writes "I would like to ask those 'Javaniers' in the Slashdot community what they thought were essential non-standard libraries that every Java coder should have. Normally I roll my own when it comes to that type of thing and simply build on whats available in the foundation classes. However, recent work has pushed me toward looking at some scientific libraries and I thought I would find out what libraries others in the Java community would consider an essential weapon in their Java arsenal. A few that I am looking at are the Cern scientific libraries and the Apache Commons Collections libraries. To avoid extra libraries I have opted to use the Java logging rather than the Apache one. Anyone like to add anything to the list?"

Comments

List (and reasons)

[sameb]

In no particular order...

Commons Logging. Yeah, you said you wanted to avoid extra libraries, but the overhead of commons logging is so incredibly small, and the extra libraries you'll want to otherwise use are going to require it anyway. It's a measly 28KB last I checked, and well worth it.

HttpClient If you want to do any form of HTTP transfers, avoid HttpUrlConnection (built in to Java) at all costs. The HttpUrlConnection code is broken in many ways (too many to list), so you'll need another library. HttpClient does a good job of hiding the HTTP transfer behind the scenes, and has easy ways of letting you extend/change what you need.

JGoodies Looks Swing is getting better every day, but for that extra polish, you'll want to use the JGoodies Looks library. It does a great job of making Metal look just that much better, and also helps out the Windows L&F in some places.

Xerces I'm not sure if the bulk of this is included in the latter versions of Java, but Xerces is definitely a must-have for any XML parsing.

Other goodies...

For rendevous (multicast DNS) support, use jmDNS. It just works.

If you need i18n handling (normalization, etc..), IBM's icu4j does a great job.

My top 5

[jacoberrol]

These are my top 5

• Logging - log4j (I agree with the previous poster. Don't write log4j off)
• Unit Test - junit
• Xml Serialization - xstream (very light-weight and easy to use object->xml serialization )
• Data access - iBATIS (a beautifully simple data access layer)
• App framework - Spring (not just for the web controller... the IoC and AOP stuff is quite nice.)

Re:Before any project...

[Earlybird]

• Unfortunately, the project never gained critical mass, so it was deemed best to close it (in August, 2004).

Wrong Commons. It's called Jakarta Commons and is alive and, despite a certain tendency to include crappy, hastily-thought-out and sloppily-designed implementations, generally considered well.

Usefull libraries

[Anonymous Coward]

We've found that the below libraries usually suit most applications:

• log4j - Killer logging tool
• ant - Killer build tool
• junit - Killer unit test tool
• xerces - XML parser

Re:cglib and more

[DreamTheater]

What's wrong with abstract base classes and inheritance? These are fundamental concepts of OO. Spaghetti code can be written in any language, regardless of these features.

My Favorites

[2starr]

GlazedLists - UI List/Table Manipulation

Doug Lea's Concurrency Utilities - If you haven't yet made the plunge to Java 5.0, this is indispensable for anything thread related.

Trove4J - High performance collections that work with primitives. We do wire-speed packet capture and flow analysis with this stuff. 'nuf said.