There are two most used java platforms: eclipse and netbeans. My choice is netbeans because it is well developed (supported by Oracle itself) and less Linux make-it-youreself like.
IntelliJ IDEA is partially free. Some features like UML integration are included only in a paid "pro" version. My latest experience with android studio shows that the platform (IDEA) is much more convenient than Eclipse, but still is not my own choice for Java development (the interface is too complicated for my liking).
I dont know why do you want to change NetBeans....? Its a good IDE and has lot of features. You can use Eclipse but for performing different kind of activities you have to download the plugins and configure them with your workbench.
I will suggest you that continue working with Netbeans......
It really depends on what you want to do in Java. For example, if you want to go for some research tool where you need to develop a plugin, then Eclipse is far better than Netbeans. For a detailed comparison, check this link
I would have to agree with Mr Zhang. If you are developing a UI, NetBeans has a well developed designer tool for this purpose, but if you are coding anything else, Eclipse is a solid, stable and actually a very lightweight IDE, compared to NetBeans.
Personally, I prefer Eclipse, mostly out of habit. Also, when developing Android applications, Eclipse is a default IDE that comes with Android Development Kit bundle.
I'd say NetBeans has pretty much all you need (it is what I am used to). But if a change is what you want, then by all means go for Eclipse as it is fully customisable and open source. Besides form design plugin (WindowBuilder) is available for Eclipse too.