The wheel is invented over and over again - at least it seems so when looking at any average Swing GUI project.
In many areas there are one or two very well known libraries for things not directly addressed by the standard class library, e.g. hibernate for persistence.
But things seem a little less clear for GUI applications - what are the libraries you see as essential for almost any new GUI project?
I'd propose JGoodies as a start. And for anything involving displaying data graphically maybe JFreeChart. For more sophisticated components SwingX - I have never used it but I hear it often mentioned.
I know there are alternatives to Swing but lets stick with at least for this question.
glazed lists for sorting and filtering lists and tables
xhtmlrenderer (flying saucer) for much better XHTML and CSS 2.1 support
swingx as you have mentioned, for the JXCollapsiblePane alone
MigLayout is an awesome layout manager. I use it it on every project I start.
Jide Common layer has some nice free swing widgets.
来源：https://stackoverflow.com/questions/4798944/essential-swing-libraries-jgoodies-jfreechart