Eclipse has extensive help and documentation, of varying age, currency, and utility. It's not unusual to discover that the documentation includes images that don't match the current version of the software, or that the keystrokes for your operating system are different from the ones called out in the help. I'm afraid it's one of the common problems with open source projects: the documentation can lag the software by months or even years. Eclipse has more than its share of documentation issues because the ecosystem is so big.
The NetBeans Java IDE started life as a university student project in Prague in 1996, became a commercial product in 1997, was bought by Sun in 1999, and was released to open source in 2000.
Oracle, which still manages and contributes to the NetBeans open source project, considers NetBeans the official IDE for Java 8. While that distinction mattered for about a month after Java 8 was released in 2014, when the other IDEs were being updated to support new Java 8 features, I'm not convinced it matters today.
Editing and refactoring
The language-aware NetBeans editor detects errors while you type and assists you with documentation popups and smart code completion. It seems to do so with less in the way of noticeable pauses than Eclipse does, although slightly more than IntelliJ IDEA. NetBeans also offers a full range of refactoring tools (shown in Figure 3) to allow you to restructure code without breaking it; performs source code analysis; and offers an extensive set of hints to quickly fix or enhance your code. NetBeans includes a design tool for Swing GUIs, previously known as "Project Matisse."
The Inspect & Transform tool enables you to run inspections across your codebase, while automatically fixing your code. Personally, I always make sure I've checked in all my code and run all my unit tests successfully before running tools that can make sweeping changes; I've been burnt more than once by automatic "fixes" that cause regressions.
Building, debugging, and profiling
NetBeans has good built-in support for Maven and Ant, and a plugin for Gradle. I was pleased to discover that existing Maven projects are now treated as "native," meaning that you simply open them rather than importing them. NetBeans also includes a sexy (and useful) graph view for Maven dependencies.
The NetBeans Java debugger is good, albeit conventional. A separate visual debugger lets you take GUI snapshots and visually explore the GUI of JavaFX and Swing applications. The NetBeans profiler is very nice for understanding both CPU and memory use, and has good tools for finding memory leaks.
Comparing the big three Java IDEs
I personally have used Eclipse, NetBeans, and IntelliJ IDEA over the years, in that chronological order. After each switch, I felt that I had improved my productivity once I got used to the new IDE. Even once I thought I had firmly switched to IntelliJ, however, there were times I had to return to one of the other Java IDEs, for example during the period when Eclipse was the only IDE supported for Android development. (Android Studio, the current official Android IDE is based on IntelliJ IDEA.)
I have full-time Java developer friends who use and swear by each of the big three IDEs. The IntelliJ IDEA users in particular are as loyal to their IDE as Visual Studio C++ and C# coders are to theirs, and claim that their productivity gains returned the cost of their annual subscriptions within a few weeks of use. NetBeans and Eclipse users are almost as loyal to their choices, and some wonder why people pay money for IntelliJ.
I tend to recommend that new Java coders not use Eclipse. Even though it's the most popular Java IDE, it has the steepest learning curve and the most potential for confusion, both in daily use and when maintaining the IDE. The many perspectives and views offer all sorts of functionality, but switching from one perspective to another can be jarring and disturb your flow.
Eclipse has the largest plugin ecosystem of any IDE, and also the greatest tendency to become unusable because of the installation of an incompatible set of plugins. Sadly, I've had to delete my broken Eclipse installation and start over with an official distribution bundle at least half a dozen times over the years. At this point, I always start fresh when a new Eclipse "release train" comes out in June.
NetBeans is good enough for most people, and has a nice profiler. I use it in a pinch, but I still prefer IntelliJ IDEA Ultimate.
For new Java coders without a budget for tools, the choice is between NetBeans and IntelliJ IDEA Community Edition. If you're coding Java servers with little or no budget for tools, then NetBeans might be the better choice, unless you fall into a category that would entitle you to a free or discounted copy of IntelliJ IDEA Ultimate, such as being a student or working on an open source project.
Project-based tips for choosing a Java IDE
I've described the notable features of each of the top three Java IDEs and offered a glimpse at a handful of lightweight alternatives. You'll need to weigh this information against your personal development needs and resources to decide which IDE will suit you best. In addition to personal considerations, there are also project-based considerations. In many cases it is easiest to use same IDE as the rest of your development team, but that isn't completely necessary.
For example, if a team project is hosted on GitHub, then your life will be easier if your IDE supports GitHub. That isn't an absolute requirement, however: you can always use a GitHub client or
git command-line and switch back and forth to your IDE. On the other hand, you really do want your IDE to support whatever build system has been adopted by the team. If it's Maven, for example, you don't want to have to reinvent the build system in Ant for your local testing. Fortunately the big three Java IDEs all support Ant, Maven, and Gradle, either out of the box or with a plugin. That isn't necessarily the case with the lightweight IDEs.
You are going to want to your IDE to support the JRE version that is standard for the project; if there's a version mismatch, you will run into bugs that the rest of the team can't reproduce. That's not a situation you want to create. Fortunately, JRE mismatches are more often configuration errors than errors caused by lack of support in the IDE: the exceptional case happens briefly when an IDE hasn't yet released an update for a new Java version.
It helps a great deal if your IDE has strong support for the frameworks and technologies used in your project. You can get by without that, but if, for example, the IDE knows how JPA statements relate to entity classes and JPA expressions (as IntelliJ does), then you are likely to spend less time on your JPA-related code. And if the IDE supports the testing framework and test runner used by the project, you'll be able to test without leaving your workspace.
Finally, it helps if your IDE can connect with whatever ticketing and bug tracking system has been adopted for the project. Again, you can get by using a standalone or web client for, say, JIRA, but you'll be more productive if you can check out your tickets directly from your IDE.
I've made a strong case for IntelliJ IDEA Ultimate, which many would consider the Cadillac of modern Java IDEs. While it's not free like Eclipse or NetBeans, I believe the productivity gain is worth the annual subscription. For developers just starting out, or those preferring not to pay, I recommend NetBeans over Eclipse. Whereas Eclipse's plugin ecosystem once made it the top choice for developers, today it has become unwieldy and somewhat poorly maintained.
I also touched on lightweight alternatives, including two designed for student use. These are worth experimenting with, and could be your best option if you are just learning Java, if you find the full-featured IDEs overwhelming, or you just like a lighter weight development environment.