BlueJ for MAC
Free, open-source Java development environment for Mac, designed for beginners and teaching, with interactive objects and Kotlin support.
BlueJ Overview
BlueJ is a development environment for writing Java programs, designed for beginners and for teaching. Its interface is deliberately smaller and simpler than professional environments such as NetBeans or Eclipse, so new programmers can start quickly without being overwhelmed. It is built around interaction: you can create objects, inspect their values and call their methods directly, and type Java expressions without compiling them first.
BlueJ was first released in 1999 and began with Michael Kölling's work on a teaching environment called Blue. It is free and open source under the GNU General Public License version 2 with the Classpath Exception. Version 6.0 added Kotlin editing and running, but some Kotlin features, such as code completion, were not yet supported at that release. It needs macOS 11 or later and has separate downloads for Apple Silicon and Intel; the version history lists the Mac downloads as including a JDK. BlueJ sends anonymous, non-personal information such as its version, the Java version and the operating system to its maintainers. You can turn this off with a bluej.uid=private setting in your bluej.properties file.
Key Features
BlueJ makes object-oriented programming something you can see.
- Simple interface: smaller than professional IDEs, on purpose.
- Object bench: create objects and call their methods directly.
- Code pad: type Java code and run it without compiling.
- Object inspection: see field values while the program runs.
- Scope highlighting: coloured code blocks help you spot misplaced brackets.
- Kotlin support: edit and run Kotlin as well as Java.
- Teaching resources: a textbook and the free Blueroom site for educators.
- Extensions and documentation: tutorials and reference material on its site.
What’s New in Version 6.0.1
BlueJ 6.0.1 is a small point release.
- Adds the missing Kotlin class templates
BlueJ FAQ
Is BlueJ free?
Yes. BlueJ is free and open source under the GNU General Public License version 2 with the Classpath Exception.
Who is BlueJ for?
Mainly beginners learning Java and the teachers who teach them. There is a textbook, Objects First with Java, and the free Blueroom site with teaching resources.
Which macOS version does BlueJ need?
The BlueJ download page says macOS 11 or later.
Does BlueJ run on Apple Silicon and Intel Macs?
Yes. There are separate downloads for Apple Silicon and for Intel Macs.
What is the object bench in BlueJ?
It lets you create objects while you work, inspect their values, call their methods and pass them as parameters, without writing a full program first.
Can I run Java code without compiling in BlueJ?
Yes. You can type Java expressions directly and see the result, then inspect it or pass it to another method.
Does BlueJ support Kotlin?
Yes. Version 6.0 added Kotlin editing and running. Some Kotlin features, such as code completion, were not yet supported at that release, and 6.0.1 adds the missing Kotlin class templates.
Does BlueJ collect data?
It sends anonymous, non-personal information such as its version, the Java version, the operating system and the interface language. You can turn this off by adding bluej.uid=private to your bluej.properties file.
Can I install BlueJ with Homebrew?
Yes. Run brew install --cask bluej.
Where does the BlueJ download on bluej.FULLMAC.app come from?
The download button leads to the official BlueJ website at https://www.bluej.org/. bluej.FULLMAC.app does not change or repackage the app.
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