Which JRE am I using?

Question

There are two varieties of JRE available. Java VM: IBM vs. Sun.

Is there a way to know which JRE I am using through JavaScript or some Java issued command.

Answer 1

The following command will tell you a lot of information about your java version, including the vendor:

java -XshowSettings:properties -version

It works on Windows, Mac, and Linux.

Answer 2

1. Open up your:
   • command prompt if you're using Windows
   • terminal if you're using mac or Linux

2. Type in:

   java -version // This will check your JRE version
   javac -version // This will check your Java compiler version if you installed the JDK
   

3. Grab a cup of coffee and you're done! You don't need to add the .exe to the java -version if everything is installed correctly.

Answer 3

Open a command prompt:

 Version:  java -version
 Location: where java (in Windows)
           which java (in Unix, Linux, and Mac)

To set Java home in Windows:

Right click on My computer → Properties → Advanced system settings → Environment Variable → System Variable → New. Give the name as JAVA_HOME and the value as (e.g.) c:\programfiles\jdk

Select Path and click Edit, and keep it in the beginning as: %JAVA_HOME%\bin;...remaining settings goes here

Answer 4

 System.out.println(System.getProperty("java.vendor"));
 System.out.println(System.getProperty("java.vendor.url"));
 System.out.println(System.getProperty("java.version"));

 Sun Microsystems Inc.
 http://java.sun.com/
 1.6.0_11

http://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html

Answer 5

I had a problem where my Java applications quit work with no discernible evidence that I could find. It turned out my system started using the 64-bit version rather than the 32-bit version was needed (Windows Server 2012). In Windows, the command:

Javaw -version

just brought me back to the command prompt without any information. It wasn't until I tried

Javaw -Version 2>x.txt
type x.txt

that it gave me what was being executed was the 64-bit version. It boiled down to my PATH environment variable finding the 64-bit version first.

Answer 6

In Linux:

java -version

In Windows:

java.exe -version

If you need more info about the JVM you can call the executable with the parameter -XshowSettings:properties. It will show a lot of System Properties. These properties can also be accessed by means of the static method System.getProperty(String) in a Java class. As example this is an excerpt of some of the properties that can be obtained:

$ java -XshowSettings:properties -version
[...]
java.specification.version = 1.7
java.vendor = Oracle Corporation
java.vendor.url = http://java.oracle.com/
java.vendor.url.bug = http://bugreport.sun.com/bugreport/
java.version = 1.7.0_95
[...]

So if you need to access any of these properties from Java code you can use:

System.getProperty("java.specification.version");
System.getProperty("java.vendor");
System.getProperty("java.vendor.url");
System.getProperty("java.version");

Take into account that sometimes the vendor is not exposed as clear as Oracle or IBM. For example,

$ java version
"1.6.0_22" Java(TM) SE Runtime Environment (build 1.6.0_22-b04) Java HotSpot(TM) Client VM (build 17.1-b03, mixed mode, sharing)

HotSpot is what Oracle calls their implementation of the JVM. Check this list if the vendor does not seem to be shown with -version.