Java In General

Hi,
In which language is the JVM coded.?
Is Java really a platform Independent Language..?
Does it work on Disk Operating System(DOS).?
How to install JVM in Disk Operating System(DOS).?



Regards,
Rahul Chandran.

Rahul Chandran wrote:Hi,
In which language is the JVM coded.?

I don't think that this is specified.

Is Java really a platform Independent Language..?

This is not entirely true as far as I know, but (again, as far as I know), it's as close as it gets.

Does it work on Disk Operating System(DOS).?
How to install JVM in Disk Operating System(DOS).?

You mean MS-DOS, independent of Windows? Is this still around? Is it still supported?

pete stein :
This is not entirely true as far as I know, but (again, as far as I know), it's as close as it gets.

Can You Tell Me The Reason Please..?

Rahul Chandran wrote:In which language is the JVM coded.?

Sun's (now Oracle's) JVM is written in C (or maybe C++) and Java. But Oracle's JVM is not the only one - other companies, for example IBM and HP, have their own JVM implementations (optimized for their servers). The code for those implementations is not open source, so nobody outside those companies really knows in what language they are written, but it's probably C or C++, since those languages are used almost everywhere for system software.

Rahul Chandran wrote:Is Java really a platform Independent Language..?

It was designed to not be dependent on platform-specific features, but you can write platform-specific Java programs (i.e., Java programs that will only work on for example Windows).

Rahul Chandran wrote:Does it work on Disk Operating System(DOS).?
How to install JVM in Disk Operating System(DOS).?

Oracle's standard JVM will not work on MS-DOS. Do you really have a computer that runs only on MS-DOS?

I found this, but this is just a kind of fun project and this is not what you want to use if you're serious about learning Java: "leDos is a tiny Java virtual machine and a set of development tools intended to allow you to develop and run Java applications on a MS-DOS system with 8088 and at least 128 KB of RAM".

You can find a list of what operating systems are supported by the standard version of Java here: Java SE 6 - Supported System Configurations.

You can find a list of what operating systems are supported by the standard version of Java here: Java SE 6 - Supported System Configurations.

"Standard" in this context meaning "released by Oracle". #6 in the JavaBeginnersFaq lists some implementations of Java (or Java-ish software) by other vendors/entities.

Jesper Young wrote :
It was designed to not be dependent on platform-specific features, but you can write platform-specific Java programs (i.e., Java programs that will only work on for example Windows).

can you tell more about that...!! please..!

if you use something like Runtime.exec() to call the Notepad.exe, that clearly wont' work on a Unix box.

Rahul Chandran wrote:

Jesper Young wrote :
It was designed to not be dependent on platform-specific features, but you can write platform-specific Java programs (i.e., Java programs that will only work on for example Windows).

can you tell more about that...!! please..!

Some examples:
Code that calls Windows native APIs via the JNI Java API.
Applications that hardcode some platform dependencies, like using a backslash as separator, in stead of using Java's built-in mechanism to retrieve the proper separator.

I can vaguely remember back in the early days of Java, that Netscape announced a plan to create a JVM that would run on 16-bit DOS machines in conjunction with Netscape running under Windows 3. They thought that supporting all that legacy hardware would give them a competitive advantage, but they totally miscalculated how quickly the hardware was changing. I'm not sure if that blunder was more a symptom or one of causes of Netscape's downfall.