Java VMs that do not require an operating system?

Question

I know that BEA was working on LiquidVM which didn't require an underlying operating system, but would like to know if anyone in the open source community is working on something similar.

Ideally I would like to find an implementation where the VM is directly loaded by the OS boot loader.

Answer 1

If you're writing a VM which runs Java apps which does not include an operating system, your VM is, by definition, an operating system. ;-)

Answer 2

There is the Sun project Squawk which a VM that runs on hardware instead of an underlying OS. Useful for embedded devices like the Sun SPOT where Squawk is the OS.

Squawk is licenced under GPLv2.

Answer 3

What is it you need?

Perhaps Sanos can give you a small chunk of code between the hardware and the JVM which you can use?

http://www.jbox.dk/sanos/

Answer 4

There's also Project Guest VM, which is a JVM hosted on Xen hypervisor. While the home page seems to be rather light on details, there's a Google Tech Talk about this project as well.

Answer 5

Hi Folks,

Just a small snippet I seen and heard.

MIT in the 60's/70's developed a Lisp machine, this was a machine that intrinsically understood Lisp, I think that they went onto commercialize it also.

I had heard in about 2002 that someone was doing to develop a JVM on a chip a FPGA or ASIC.

The MIT/Lisp story is true, I seen it in their museum, does anyone know if there is any truth about the JVM on a chip?

thanks, Martin.

Answer 6

JNode OS is an operating system written mostly in Java.

Answer 7

Unlike SANOS, the JNode operating system is a full operating system with many supported devices, file systems, a network stack, a GUI stack, a command shell and 50 or so commands, and much more. JNode currently runs on x86 (32 bit) with one processor enabled, but x86-64 and multi-processor versions are in development. (JNode is 99.99% Java. Porting to a new architecture would entail rewriting the 0.01% of code that is in assembler, creating / modifying hardware specific drivers ... and writing a native code compiler for the new architecture.)

We currently have ~7 active developers, but we are always looking for new people to join the team, especially people who understand Java AND code generation, garbage collectors, drivers and so on.

Answer 8

I am very new to java and and i have some knowledge of electronics.

JVM is a virtual macjine which actually run over a system. It may be windows or solares x86 platform. But as far as i know JVM itself act as a system for the Bytecode that we compile. For a byte code JVM virtualise its own ALU, Heap, Stack extra. It even have its own machine and assmbly language.

So some how if we able to realize a JVM specification on a Hardware chip then it will not be JVM anymore but i will become standalone Java Machine over which we can develop a operating system 100% written in java.

So in this case JVM will not be an OS but a System which directly understand java bytecode.

Answer 9

Oracle seems to work again in that direction

Gained with Oracle's acquisition of BEA Systems ... Oracle has resuscitated avant-garde virtualization technology: a Java Virtual Machine that runs directly on the hypervisor, without an operating system.

see

• Virtualizing the JVM
• Oracle one-ups VMware with Java virtualization