Typed OS to very securely execute programs, which can only manipulate defined type variables, not memory spaces; avoids many problems caused by programming in languages such as C. French initiative, binary fits one floppy disk. [Open Source]

Goals: all Java OS, flat memory model, for personal use, simple to use and install, any Java applications to run on it fast and safe. Descriptions, documents, screenshots, downloads. [Open Source, LGPL]

Collaborative undertaking by an international group of Java programmers and enthusiasts to create free Java OS. [Open Source]

JX OS: set of Java components executes on core doing system initialization, CPU context switching, low-level domain management; code organized as components loaded into domains, verified, translated to native code; protection based on only type safety of intermediate (byte)code. [Open Source]

Tiny Java OS for Lego RCX brick. Like its predecessor TinyVM, has tiny Java runtime, under 32K; works as replacement firmware for Lego; Hitachi H8300 processor. To be ported to more small devices. [Open Source, Mozilla]

Multitasking environment, written in Java, for all Java programs, can execute many Java applications in unique virtual machine. Descriptions, screenshots, downloads. [Open Source, GPL]

Tool designed to teach inner workings of operating systems: simple animated simulated OS and hardware coded in Java. RCOS successor.

Minimal OS kernel for PC based server appliances. Lets you run java server applications without need to install host OS, only need normal Java HotSpot VM and Sanos. Description, documents, downloads, manifesto, links, contact. [Open Source, BSD]

Developer of SavaJe OS for advanced mobile phones. Offers company overview and list of partners.