IntelliJ IDEA 45 alternatives | Website
IntelliJ IDEA is a free / commercial Java IDE by JetBrains. Its design is centered on programmer productivity. A number of its features are intended to accelerate development and allow programmers to concentrate on functionality while IntelliJ IDEA handles routine coding tasks.
IntelliJ IDEA is available in two editions: Ultimate (paid) and Community (free and opensource).
The Community Edition is Open Source but misses most features for server-side and web development.