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sameerkhanpqr 03-14-2016 01:37 PM

Java versions in Unix
 
Hello, Kindly help me in below queries :

1. Can we have more than one installation of JVM in a single unix machine ?

2. If yes, then command to findout all the versions of JVM available ?

3. what would be the result of java -version in such a system ?

4. What do we have to set for JAVA_HOME in such a system ?

5. how to find out the vendor of JAVA of all the versions ?

6. Why we are still using OpenJDK when there is OracleJDK available ?

7. jps command when ran shows not found ???

8. How can i point my application to use a specific java version in such a system ?

9. Among all these versions in a single machine, will there be only one active version of java and rest all will be idle ??

BW-userx 03-14-2016 02:20 PM

Answered within the quote after the actual question:
Quote:

Originally Posted by sameerkhanpqr (Post 5515328)
Hello, Kindly help me in below queries :

1. Can we have more than one installation of JVM in a single unix machine ?
Yes

2. If yes, then command to find out all the versions of JVM available ?

which java
or
whereis java


3. what would be the result of java -version in such a system ?
Give it a shot and find out for yourself, or I do not understand this question. Pls rephrase the question.

4. What do we have to set for JAVA_HOME in such a system ?
the actual path to javac

5. how to find out the vendor of JAVA of all the versions ?
refer to question 2

6. Why we are still using OpenJDK when there is OracleJDK available ?
Because OpenJDK is open source whereas OracleJDK is not open source.
OpenJDK actually came after OracleJDK which was written and had been in circulation long before OpenJDK came into being.

Look what the search engine has to say about it for further information

7. jps command when ran shows not found ???
refer back to question 4 or question 2

8. How can i point my application to use a specific java version in such a system ?
absolute path

9. Among all these versions in a single machine, will there be only one active version of java and rest all will be idle ??

they all lay dormant until needed, then it all depends on how you deal with it in setting it up to let everything that will be using all of these different versions of Java otherwise it will totally confuse the system or application trying to use it actually if you do not provide it with the proper information to operate under such conditions. due to deprecated function calls that maybe within the code, methods typed the same as well. You're better off keeping it updated due to deprecated functions unless otherwise specified from a vendor.



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