BlueJ vs CS++ Java IDE

BlueJ is a free development environment for building Java programs, designed for beginners and teaching. It runs on Windows, macOS and Linux, with current downloads requiring a 64-bit operating system. Its interactive tools let users create and inspect objects, call methods, and evaluate Java expressions without compiling. In the editor, scope highlighting distinguishes code blocks and can help reveal misplaced curly brackets. BlueJ 6.0.0 added Kotlin editing and execution, though some Kotlin features, including code completion, are not supported. Documentation includes a Git teamwork tutorial for BlueJ 4 and later. Third parties can add functionality through an extensions API; the listed extensions page covers BlueJ 4 and older, while BlueJ 5.0.0 rewrote the API. The free Blueroom site offers teaching resources for educators. BlueJ directs software questions to its FAQ, technical support contact and bug database, and says it aims to respond to technical support requests within one working day.

CS++ Java IDE lets users write and run Java in a browser without installing a JDK. Its custom interpreter handles most of Java and core standard-library features, including classes, generics, collections, lambdas, and streams. A step-through debugger and clear error messages are included for beginners. The runtime does not support threads, writing files, reflection, enums, records, or switch expressions. The browser IDE works on Chromebooks, iPads, phones, Macs, and Windows PCs, including locked-down school devices. Users can begin without an account; signing in is optional and adds cloud saving across devices. Teachers can share starter code and worked examples by link, and use the IDE for demonstrations and homework. It is aimed at beginners and AP Computer Science A students, with supported topics extending beyond the exam to generics, collections, lambdas, and streams. The free plan supports writing, running, and auto-testing Java in a browser without signup to start. The listed pricing note says paid access starts at $9.99, though no paid plan details are provided here.