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Can we run multiple java versions in parallel for different purposes?

I am using Elasticsearch which uses Java 8. I also want to install kafka on the same machine but kafka uses java 11. Both services are to be run in parallel. Can anyone tell how can I run both java versions at same time?

Manually download and unpack Java
https://adoptium.net/releases.html?variant=openjdk11
https://www.azul.com/downloads/?version=java-17-lts&os=windows&architecture=x86-64-bit&package=jre
Instead of simply starting java with the
java -args commandline,
you can start it via /install/path/to/java/bin/java -args
or, for windows, use C:\install\location\bin\java.exe -args
You might want to make some start scripts / batch files for that, depending on the exact requirements of your system and Elasticsearch and kafka and possibly other software.
That's it.
one little addition:
If you can NOT directly call java, or the software starts more java apps via the 'default' java, you can also use scripts to manipulate the PATH variables of your system before starting the app. Then you (and your apps) can simply call java -args again.

Once you download different versions of JRE(java runtime environment) to your local, if you use Eclipse IDE, you can checkout different projects in single workspace & specify Java Build Path with JRE version you want.
This way, you can run multiple applications having different versions of Java.
I think other java IDEs also have this kind of support.

How to run existing JAVA Web start application in java 10 or later java 11

My application is developed in java Swings which is 20 years old. For this huge application we are migrating the same on JAVA 10 now and will migrate the same on java 11 or upcoming versions. This application is working fine with java Webstart and as per the java 11 features, java Web Start application will not be supported in java 11 and other coming versions.
Please let me know the best way to run my application on java 10 with out webstart.

There is OpenWebStart start project. It says:
we decided to create OpenWebStart, an open source reimplementation of
the Java Web Start technology. Our replacement will provide the most
commonly used features of Java Web Start and the JNLP standard, so
that your customers can continue using applications based on Java Web
Start and JNLP without any change.
At the moment the project is alpha phase. Download is available. Beta should be available by the end of the year:
Our goal is to have beta tests and a release candidate ready in
Q3/2019

One solution might be the WebStart replacement that Karakun is currently working on: https://dev.karakun.com/webstart/
Currently it is not clear when and how this will come since it is based on a kind of crowd-founding but since everyone can get involved (even with low cost) this is a very good possibility.
Since this is a duplicate of Applet/JNLP on Java 11 migration I just copied my answer

Use Getdown which is a system for deploying Java applications to end-user computers, as well as keeping those applications up to date.
It was designed as a replacement for Java Web Start due to limitations in Java Web Start's.
You can read more on https://github.com/threerings/getdown

You will have to find an alternative technology to JWS/JNLP to run your system, as JWS/JNLP will no longer be available.
I don't have a clear cut alternative, the few companies still using JWS tend to be working to develop their own replacements for internal use.
I know this may not be what you want to hear (that there is no out of the box replacement available) but that's the way it is. Project I'm working on is in a similar conundrum, we also have several JWS components that will need to be reworked in the near future.

where can I download Java 8 base profile?

I am under the impression that with version 8, we would be able to download parts of the jdk we need and it will be full functional. I am unable to locate java 8 compact profile anywhere. (not the early access versions)

Short answer: try this link. It only works for Java embedded.
Long answer: Java embedded is a version of Java with specific modifications for the embedded market. Profiles is one of those features. Here is a tutorial for java profiles
As you can see in the power point (page 20 and 21) of this oracle presentation you have two choices: a reference implementation built for demostrations purposes or Java embedded.
Just to address some comments:
Jigsaw project was delayed to Java 9 but part of this work made its way into Java 8 in the form of Profiles

Deploying Java 7 applications on Mac

I need some pointers to relevant information.
I'm trying to generate a Mac application bundle that contains a Java program. For Java 6 this is fairly easy.
But as far as I know, Java is no longer included with OS X, and in particular there is no guarantee that Java 7 is installed on a user's Mac computer.
Googling only brings confusion. There are hundreds of web pages that tell you how to deploy Java on a Mac, and there are dozens of tools that help you generate the application bundes. The problem is that most of these were written for creating applications that use Java 6. I have not yet found relevant information that I can use with Java 7.
So,
Where can I find information about how to deploy Java 7 applications on a Mac?
Is it possible to include the Java 7 VM in the application bundle, or do the users have to dowload and install it separately?

Two copy of Java in JWS

I am working with Java web start. After launching application with Java web start, it checks for java environment in our system. If required java version is not found, then it downloads appropriate version to our system for that application only,but not affecting the system environment.
My question is that if in my system there are Java1.3. and I am
launching 2 or more than 2 different applications using Java web
start,which all required java 1.6 . Then are they all downloads
different copies of java? If yes,then there is any way that only one
copy of java should get downloaded.

Then are they all downloads different copies of java?
No.