Why java is platform independent ?

what is the meaning of java is platform independent ? is it just because of java code can be run in windows/linux/unix platform ? but then C/C++ also can be run in windows/linux/unix . so why those are not called platform independent ?
why java is called platform independent ?

c/c++ creates object code . similary java creates bytecode . java uses interpreter JVM to execute . similary c/c++ object code also executes in any platform. so where is the real difference ?
the classes do not need to be recompiled for different platforms. what do u mean by this ? ".....classes ( i.e bytecode) dont need recompilation ..." .....ok....but same thing is true for C/C++ object code also !! they also dont need recompilation.
where is the difference ?

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How do u say java is platform independent

how do u say java is platform independent.....when a .class file for a program cannot be executed in another system with no java installed in it.......

Pictograms are language independent (sort of)
do you expect them to work in the land of the blind?

Java is Platform Independent - good, but why is it not version independent?

Dear developers,
Development in java is becoming so independent to its versions. The code which works fine on 1.2.0 may or may not work on 1.3.1 and which works on 1.3.1 dont work fine on 1.4.0. I have been experiencing these problems from quite a few time. So i just want to know am i doing a mistake or java is like that only.
And even if a code works fine on 1.4.1 with using only methods and classes available right from 1.2.0 also didnt work properly on 1.2.0. So how can we go confidently in to Production.
Problems faced in GUI using Swing Components and In Socket Connections using HttpURLConnection kind of code.

Development in java is becoming so independent to its
versions.Actually Development in java is becoming so dependent to its
versions is what i mean.

Tips on avoiding hard coded paths and make a java app platform independent

HI all,
I would like to gather some tips on how to avoid hard coded file paths, which are plenty in the application I work on and which I inherited from previous programmers.
Also, when deploying to the production server, my app goes from a Windows platform to a Linux machine.
I am curious to know what tricks and tools other programmers find useful in similar contexts.
I am sure many of us would benefit from the discussion.
Thank you !

Actually, Java does this for you; you can use unix-style paths and they will still work, even on Windoze. To wit:
public static void main(String[] args) {
        File f = new File("/");
        System.out.println(f.getAbsolutePath());
}Yields: C:\
public static void main(String[] args) {
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}Yields: C:\Program Files

How java is platform independent

in java we need jre to be present in target machine?
in that case how its possible that we should expect jre to present in tha target machines
why cant we have inbuilt compiler and interpreter that produces the common machine specific code that does not needs the help for jre to run?????

in java we need jre to be present in target machine?
in that case how its possible that we should expect
jre to present in tha target machines
why cant we have inbuilt compiler and interpreter
that produces the common machine specific code that
does not needs the help for jre to run?????it's possible that we can expect the JRE to be present in target machines because you can specify that a JRE is a prerequisite to your customers. of course, oftentimes one can just ship a compliant JRE with your application. that's what we do, which guarantees us that the target machine has a JRE and it's compliant with our code
what does 'inbuilt' mean? to the target machine? how do you enforce that?? if you mean inbuilt to your code, see above

Why java is called platform independent? "write once, run anywhere" code...

I do have a answer for this. Please shed some light whether i am right or wrong.
When you say java as platform independent, it means that, any java program once compiled to java class can be transferred to anyother machine(say, from windows to unix) can be executed, provided the destination machine has JVM.
where as, in C/C++, if we transfer the object files from one machine to another machine, they will not be executed and they have to be re-compiled in the other machine.
Am i correct?
please, do give me your idea on this...
thanks...

Thanks george !

Java platform independent.what is a platform?

This question has been haunting me for a long time.
When we say Java is platform independent,what does the term platform
indicate?
I think it is Processor+Operating System.
But people talk only of Operating System as platform.
A processor has its own instruction set that is different from that of other processors.An executable code on one processor doesn't run on another processor,whatever may be the operating system.
Java code is platform independent because it is just compiled to byte code and that byte code is interpreted and run on a JVM.Here the JVM is different for different platforms.
My question is:
consider two platforms:
Intel Pentium+MS Windows.
and AMD Athlon+MS Windows.
Is the same JVM used for both these platforms?or not?WHY?
If only Operating System is Considered as platform,what happens to the underlying processor?

<troll style="flamesuit: on;">Java is not plateform inderpendent, java runs on one plateform, the Java Platform.</troll>
The "Intel / AMD + MS Windows" is two forks of one plateform, the x86 / Windows plateform.
You could extends the x86/Windows JVM to include Intel extras in such a way that it would not run on AMD/Windows.
One way you could define a plateform is as a binary format, processor intuction set and public API.
So java == .class format, bytecode and the java.* packages
and Linux x86 == ELF, x86 and POSIX (plus others, such as X)
and FreeBSD x86 == ELF, x86 and POSIX (plus others, such as X)
and Cygwin == ELF, x86 and POSIX (plus others, such as X)
and Windowsx86 == PE, x86, MFCs
But does that mean Linux, FreeBSD and Cygwin are the same plateform, well kind-of, they are all unix-sqe, and in some cases the binarys are interchangable (a small plug in to FreeBSD will let you run Linux software, the same sort of thing is aviable to Solaris, and some very small (hello world-level) will actually run (I've seen this in the case of a Linux HelloWorld on a BeOS machine).

Java is NOT Platform Independent ????????

Hai.
My friend told ...
we can able to say java is platform independent.
but
in one company (software anaylist) ask
talk about java is not platform independent...
so how its possible..
plz i want clear cuts...
even i search in google also.. but i cant get clearlly.........
yours
advance happy pongal and upcomming festivals
drvijayy2k2

>
A quick example I recently encountered of platform
dependence was in character encoding/decoding. Have
a look at how Solaris, Linux and Windows print out
the full range of bytes when they are encoded as
Strings. There are lots of little differences, happy
discovering.This is a good illustration. By default java uses the character encoding which it believes to be in general use on the platform it's running on, but you can specify the character encoding explicitly. So, by default, the Java program addapts it's exact behaviour to the platform.
Is "a platform independant" program one which produces the same file format on systems which will interpret that file format different ways? Or is it one that generates a file format that will produce equivalent results on two different systems?
There's a similar dilema with "look and feel" (i.e. window gadgets etc.). Should a platform independant program use the same look and feel on systems whose native look and feel is different, or should it "blend in"?
Java leaves these choices to the programmer.

Platform Independent

Java is platform independent.What do u mean by paltform independent?

platform Independent does'nt mean once compiled
its means it can run without the help of platorm(os)
jvm provides pltfom indepent to java but
jvm is also os specific means there is different jvm for widows ,
different for linux,and diiferent for mac
there is two layers in jvm
first interact with byte code
& second interact with platform(os)
in mobile applicatoin jvm directly produce output bcz jvm is interpreator

Platform independency...any chance ?

hi...java code (.class files ) are platform independence. It is supposed to run any platform.(i believe this) [ // it is fine in different windows machine ].
However, i was in argue with my friend..... He told that each platform (windows,Unix,Macintosh) have different JVM . so there is a chance that the class file may be rejected by the JVM in different platform.
is it true ?
if Yes.......then independency is lost !!! i can not call it is a pure platform independent.......are people trying for any remedy ?

There are many different JVMs. Sun makes JVMs, IBM makes JVMs, M$ used to make JVMs, I think Blackdown makes JVMs, etc.
As long as a JVM matches the spec, then a given class file is portable across different VMs. Just like if I create a Word doc on the PC, I can read it with word on my Mac.
BUT (you knew there was going to be a "but", didn't you), there are different versions of VMs and the spec has changed over the years. Just like MS Word from 1990 probably won't read a document you create with the MS Word that you buy today, similarly you need to make sure the version of your class file is no newer than the VM. If the class file is an older version than the VM, it will generally work--they're backward compatible that way. Or is it forward compatible.
Also, there are things that are legal Java code that won't necessarily translate from one platform to another that well. GUI stuff can be slippery that way, I understand. Some other things too, but I forget what.
Is Java perfectly platform independent in that any class file generated anywhere anytime is guaranteed to run on any other VM? No, of course not.
Is it easy to create applications that you can run with no changes on Mac, Windows, Linux, Solaris, and maybe others that I'm not aware of? Absolutely. Many of the apps I've developed in the last few years have been developed and unit-tested on Windows (and even Mac to some extent) and run on Linux or Solaris, without me even needing to think about it. (Not that you never need to think about it, but it's not an overriding concern.)

Why java is called platform independent

Hello
Why java is called as platform independent?Any body please give a detailed explanation since im a beginner to java technology.
ThankYou
Jk

BigDaddyLoveHandles wrote:
georgemc wrote:
SunFred wrote:
Java is not platform independent since it depends on the Java platform ;)Don't complicate matters!I always thought the phrase should have been "platform agnostic"It's a phrase I've used meself

Determining free disk space in a platform independent "java-like" way?

how can i determine free disk space in a platform independent "java-like" way?

Search the forum "free disk space".

Need platform independent java code for TNS PING

Hi, I am able to ping server /ip address. but unable to ping some TNS entry.
There is one way to ping TNS entry using System command, but that will make my code platform dependent. i want platform independent code.. need code help for TNS Ping to database server.. here are my code:
---Code for server / Ip address ping:---------
package DBM;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import oracle.net.TNSAddress.*;
public class PingServer
public static void main(String[] args)
System.out.println(" Server Pinging Starts...");
ArrayList<String> list=new ArrayList<String>();
list.add("g5u0660c.atlanta.hp.com");
list.add("g1u1675c.austin.hp.com");
list.add("gvu1785.atlanta.hp.com");
list.add("10.130.14.109");
list.add("10.130.0.173");
list.add("DESCRIPTION = (SDU = 32768) (enable = broken) (LOAD_BALANCE = yes) (ADDRESS = (PROTOCOL = TCP)(HOST = gvu1515.atlanta.hp.com)(PORT = 1525))(ADDRESS = (PROTOCOL = TCP)(HOST = gvu1785.atlanta.hp.com)(PORT = 1525)");
list.add("IDSENGI");
//This Ipadd variable is used to convert the arraylist into String
String ipadd="";
try
     for(String s: list)
          ipadd=s;
          // InetAddress is class.in this class getByName()is used to take only string parameter.
          InetAddress inet = InetAddress.getByName(ipadd);
          //InetAddress inet1 =InetAddress.getAllByName("IDESENGP");
          System.out.println("Sending Ping Request to " + ipadd);
          //in InetAddress call IsReachabe(3000)method is used to ping the server IP and if ping is successfully then return true otherwise false.
          //IsReachable()take time in millisecond and return type is boolean.
          System.out.println("Host is reachable: "+inet.isReachable(3000));
     System.out.println("Server Pinging program is working fine........");
catch (UnknownHostException e)
     System.err.println("Host does not exists");
catch (IOException e)
     System.err.println("Error in reaching the Host");
----Code for TNS ping using system host----
package DBM;
import java.io.*;
public class doscmd
public static void main(String args[])
try
Process p=Runtime.getRuntime().exec("cmd /c tnsping IDSENGP");
p.waitFor();
BufferedReader reader=new BufferedReader(new InputStreamReader(p.getInputStream()));
String line=reader.readLine();
while(line!=null)
System.out.println(line);
line=reader.readLine();
catch(IOException e1) {}
catch(InterruptedException e2) {}
System.out.println("Done");
The above two codes are working absolutely fine... but need TNS ping program is platform dependent..we need to deploy it in both windows, unix...
Please help.

You don't need to install another JDK, just use the api from 1.2 and you should be fine. You can even use the 1.4 jdk to compile as if it were 1.2 by using the -target option in javac.

Is Java Byte Code is 100% platform independent

Hi all
A my room fellow is disturbing me about the platform independency of JAVA.
Now i only wan to know that generated Byte Code will be same if it is generated on different platforms (Window,Linux,Unix etc)using their respected JVM
Thanks in advance

The "Platform Independency" of Java is a bit of a joke
to me. You need a JVM that is platform dependent to
run it. Now granted, you can write one application
and itll run on any platform, but that's only assuming
they have the JVM installed on them. Not to say that
Java isn't cool and all, but the "platform
independency" solution still has a reliance on
something that is platform dependent... It's like
driving an automatic and saying you can drive....Sure,
you are making the car go, but something is doing the
shifting for you....(C: I guess I'm just arguing for
the sake of arguing...Well if you want to argue that point then no language is platform independant. C code for instance needs a compiler for the platform you want to compile it to run on and that compiled code won't work on any other platform. Ultimately every program has something that ties it to a particular platform, that's just the nature of things in computers.
The idea of platform independance was the removal of the need to re-compile a program with a native compiler just to get it to run on that platform.
Instead Sun opted to have a compact JVM to interpert the byte code and have the byte code standard across all implementations of the JVM.

Java ME Platform SDK - S60 Emulator Problem

Hi Everyone!
I am new to S60 development. I searched the forum, and some other discussion forums but could not find any solution to my problem (If there is one in this forum, sorry about that).
I installed Java ME Platform SDK 3.0 Early Access. I also installed Java SDK for S60-FP1, and added this platform to my IDE with no problems.
The problem is, I can write and execute my code on S60 emulator, but Java IDE has got this annoying exception blinking on the bottom right side saying: "java.lang.IllegalArgumentException: Device S60Emulator not registered!". As I said, I can run the application, but I cannot debug because of some exceptions!
Why this can be happening, can it be a misconfiguration or something?
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Did you check Release Notes of the SDK? I've seen it once - if memory serves it lists quite a lot of known bugs.
Maybe the problem you describe is listed there too... and if you're really lucky then description may even mention some workaround for it.

Why java is platform independent ?

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