RSS

To check java installation (jdk /jre) on computer

Please support our Java advertiser: Lunarpages Java Web Hosting

Views: 3111 | Replies: 8 | Thread Tools Display Modes

•

Join Date: Jan 2008

Posts: 4

Reputation: shankarjadhav is an unknown quantity at this point

Rep Power: 0

Solved Threads: 0

shankarjadhav shankarjadhav is offline

Offline

Newbie Poster

To check java installation (jdk /jre) on computer

Jan 29th, 2008

Guys,
How to check for java installation in windows, i want some code/pseudo code/algorithm..
Help me out.....

•

Join Date: Jul 2007

Posts: 31

Reputation: ksaxena is an unknown quantity at this point

Rep Power: 2

Solved Threads: 4

ksaxena

Offline

Light Poster

Re: To check java installation (jdk /jre) on computer

Jan 30th, 2008

use java -help on command line to find various options which you may use to get information about JRE installation on windows.

•

Join Date: Aug 2006

Location: South Africa, Durban

Posts: 129

Reputation: PoovenM is an unknown quantity at this point

Rep Power: 3

Solved Threads: 11

PoovenM

Offline

Junior Poster

Re: To check java installation (jdk /jre) on computer

Jan 30th, 2008

Interesting, well on the command line one would type java -version but you want to execute code within your program to determine the runtime version. Well I think this should work:

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
Process java = Runtime.getRuntime().exec("cmd /C java -version");
BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream()));
String line;
while ((line = in.readLine()) != null)
    System.out.println(line);
Process java = Runtime.getRuntime().exec("cmd /C java -version");
BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream()));
String line;
while ((line = in.readLine()) != null)
    System.out.println(line);

It should give you the following output from which you could extract the version:

Help with Code Tags

(Toggle Plain Text)

java version "1.6.0_03"
Java(TM) SE Runtime Environment (build 1.6.0_03-b05)
Java HotSpot(TM) Client VM (build 1.6.0_03-b05, mixed mode, sharing)

However, it doesn't work

Well at least you have something to work with... sorry mate.
Oh and the command I executed is a Windows based command that will not work on Linux.

Last edited by PoovenM : Jan 30th, 2008 at 6:22 am. Reason: After thought

•

Join Date: Jan 2008

Posts: 4

Reputation: shankarjadhav is an unknown quantity at this point

Rep Power: 0

Solved Threads: 0

shankarjadhav shankarjadhav is offline

Offline

Newbie Poster

Re: To check java installation (jdk /jre) on computer

Jan 31st, 2008

•

Originally Posted by PoovenM

Interesting, well on the command line one would type java -version but you want to execute code within your program to determine the runtime version. Well I think this should work:
Help with Code Tags

java Syntax (Toggle Plain Text)
Process java = Runtime.getRuntime().exec("cmd /C java -version");
BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream()));
String line;
while ((line = in.readLine()) != null)
    System.out.println(line);
Process java = Runtime.getRuntime().exec("cmd /C java -version"); BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream())); String line; while ((line = in.readLine()) != null) System.out.println(line);
It should give you the following output from which you could extract the version:
Help with Code Tags

(Toggle Plain Text)
java version "1.6.0_03"
Java(TM) SE Runtime Environment (build 1.6.0_03-b05)
Java HotSpot(TM) Client VM (build 1.6.0_03-b05, mixed mode, sharing)
java version "1.6.0_03" Java(TM) SE Runtime Environment (build 1.6.0_03-b05) Java HotSpot(TM) Client VM (build 1.6.0_03-b05, mixed mode, sharing)
However, it doesn't work Well at least you have something to work with... sorry mate.
Oh and the command I executed is a Windows based command that will not work on Linux.

Thank u dude...
Let me try...

•

Join Date: Jan 2008

Posts: 4

Reputation: shankarjadhav is an unknown quantity at this point

Rep Power: 0

Solved Threads: 0

shankarjadhav shankarjadhav is offline

Offline

Newbie Poster

Re: To check java installation (jdk /jre) on computer

Jan 31st, 2008

•

Originally Posted by shankarjadhav

Thank u dude...
Let me try...

I tried with the following program

class test{
public static void main(String args[]){

Process java = Runtime.getRuntime().exec("cmd /C java -version");

BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream()));

String line;

while ((line = in.readLine()) != null)

System.out.println(line);
}
}

saved as test.java, when i compiled this, it gives error "cannot read test.java"

•

Join Date: Aug 2006

Location: South Africa, Durban

Posts: 129

Reputation: PoovenM is an unknown quantity at this point

Rep Power: 3

Solved Threads: 11

PoovenM

Offline

Junior Poster

Re: To check java installation (jdk /jre) on computer

Jan 31st, 2008

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
class Test
{
	public static void main(String args[]) throws IOException
	{
		Process java = Runtime.getRuntime().exec("cmd /C java -version");
		BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream()));
		String line;
		while ((line = in.readLine()) != null)
			System.out.println(line);
	}
}
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

class Test
{
	public static void main(String args[]) throws IOException
	{
		Process java = Runtime.getRuntime().exec("cmd /C java -version");
		BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream()));
		String line;
		while ((line = in.readLine()) != null)
			System.out.println(line);
	}
}

Well there are a few imports that you must first have, though I've never seen such an error. What IDE are you using? On and Test is prefered over test for class file names

But for me this code has no output

•

Join Date: Jan 2008

Posts: 4

Reputation: shankarjadhav is an unknown quantity at this point

Rep Power: 0

Solved Threads: 0

shankarjadhav shankarjadhav is offline

Offline

Newbie Poster

Re: To check java installation (jdk /jre) on computer

Jan 31st, 2008

•

Originally Posted by PoovenM

Help with Code Tags

java Syntax (Toggle Plain Text)
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
class Test
{
	public static void main(String args[]) throws IOException
	{
		Process java = Runtime.getRuntime().exec("cmd /C java -version");
		BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream()));
		String line;
		while ((line = in.readLine()) != null)
			System.out.println(line);
	}
}
import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; class Test { public static void main(String args[]) throws IOException { Process java = Runtime.getRuntime().exec("cmd /C java -version"); BufferedReader in = new BufferedReader(new InputStreamReader(java.getInputStream())); String line; while ((line = in.readLine()) != null) System.out.println(line); } }
Well there are a few imports that you must first have, though I've never seen such an error. What IDE are you using? On and Test is prefered over test for class file names But for me this code has no output

Dude, no out put

...

•

Join Date: Aug 2006

Location: South Africa, Durban

Posts: 129

Reputation: PoovenM is an unknown quantity at this point

Rep Power: 3

Solved Threads: 11

PoovenM

Offline

Junior Poster

Re: To check java installation (jdk /jre) on computer

Feb 1st, 2008

hehe yeah that's what I said! but it was suppose to work. For example, instead of cmd /C java -version try using cmd /C dir and you'd get the output from the command prompt. Does anyone have any ideas?

•

Join Date: May 2007

Location: USA

Posts: 3,345

Reputation: Ezzaral is a splendid one to behold

Rep Power: 16

Solved Threads: 333

Ezzaral

Offline

Nearly a Senior Poster

Re: To check java installation (jdk /jre) on computer

Feb 1st, 2008

Well, that is about the longest way around the problem if you simply want to know the java version from within a program. All you need is

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
System.getProperty("java.version");
System.getProperty("java.version");

There is a lot of other info available as well

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
        for (java.util.Map.Entry s : System.getProperties().entrySet())
            System.out.println(s.getKey()+": "+s.getValue());
        for (java.util.Map.Entry s : System.getProperties().entrySet())
            System.out.println(s.getKey()+": "+s.getValue());

But all that is completely irrelevant if you are trying to check to see if java is installed on a machine. If Java isn't installed, Java code won't run. You will need a batch script or something else if you want to check for Java before running or installing an application.

The original poster does not explain the context, nor what the he/she needs to do with that information. Without a little more detail, you can't really provide a sufficient answer.