BlueJ
What it is
BlueJ is a free development environment for creating Java programs, designed with beginners and teaching in mind. It runs on Windows, macOS, and Linux. Users can inspect objects, create them dynamically, invoke methods, and evaluate Java expressions without compiling. The editor uses scope highlighting to distinguish code blocks and help identify misplaced curly brackets. BlueJ 6.0.0 added Kotlin editing and execution, but some Kotlin features, including code completion, are not supported. Documentation includes a Git teamwork tutorial for BlueJ 4 and later. An extensions API allows third parties to add functionality; the extensions page says its listed extensions are for BlueJ 4 and older because version 5 rewrote the API. Current download requirements include 64-bit Windows 8 or later, macOS 11 or later, or 64-bit Intel Debian 11 or Ubuntu 20.04 or later; an ARM64 build is also linked for Ubuntu and Debian. The project was first released in 1999. Educators can also use the free Blueroom site for teaching resources and to engage with one another.
For and against
For
- Free Java development environment
- Interactive object and expression tools
- Scope highlighting in the editor
- Runs on Windows, macOS, and Linux
- Free teaching resources through Blueroom
Against
- Some Kotlin features are not supported
- Listed extensions are for BlueJ 4 and older
- Some written documentation is out of date
- Requires a 64-bit operating system
The verdict
BlueJ focuses on Java development with interactive tools and an interface designed for learning. Kotlin support has limits, and users should check the stated system requirements and documentation status before installing.
Who it suits
BlueJ is intended for beginners and teaching, making it a fit for people learning Java and educators. The free Blueroom resources are aimed at educators.
Plans and prices
BlueJ
Free Java development environment; designed for beginners
Read 3 Oct 2026 · bluej.org
On the record
- Audience and education resources
- BlueJ is designed for beginners and teaching, and its free Blueroom site offers teaching resources and a chance for educators to engage with one another.bluej.org · read 3 Oct 2026
- Documentation limit
- The documentation page says some written materials are out of date and that updated reference material is in progress.bluej.org · read 3 Oct 2026
- Editor
- The editor uses scope highlighting to distinguish code blocks and help users spot misplaced curly brackets.bluej.org · read 3 Oct 2026
- Extensions
- BlueJ provides an extensions API for third parties to add functionality; its extensions page notes that BlueJ 5.0.0 rewrote the API and that the listed extensions page is for BlueJ 4 and older.bluej.org · read 3 Oct 2026
- Git integrations
- The documentation provides a Git teamwork tutorial for BlueJ 4 and later.bluej.org · read 3 Oct 2026
- Interactive tools
- Users can inspect objects, create them dynamically, invoke their methods, and run Java expressions without compiling.bluej.org · read 3 Oct 2026
- Languages
- BlueJ 6.0.0 added Kotlin editing and execution, while the release notes say some Kotlin features, such as code completion, are not yet supported.bluej.org · read 3 Oct 2026
- Operating system requirements
- The current download page specifies 64-bit Windows 8 or later, macOS 11 or later, or 64-bit Intel Debian 11 or Ubuntu 20.04 or later; it also links an ARM64 build for Ubuntu/Debian.bluej.org · read 3 Oct 2026
- Other platforms
- The site says the generic installer works on most platforms with Java/JavaFX 21 support and that BlueJ requires a 64-bit operating system, with version 4.1.4 offered for 32-bit systems.bluej.org · read 3 Oct 2026
- Project history
- The about page says BlueJ was first released in 1999 and that its team works in the Computing Education Research Group at the University of Kent.bluej.org · read 3 Oct 2026
- Purpose
- BlueJ is a development environment for developing Java programs, designed with a simple interface and teaching in mind.bluej.org · read 3 Oct 2026
- Security
- The official pages reviewed do not state a security certification or compliance claim.bluej.org · read 3 Oct 2026
- Support
- BlueJ directs users to its FAQ, technical support contact, and bug database for software issues, while recommending programming forums for programming questions.bluej.org · read 3 Oct 2026
- Support response
- The about page says the team aims to respond to technical support requests within one working day.bluej.org · read 3 Oct 2026
