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I am using java-8 for multiple spring-boot projects but now one of them needs to be shifted to java-11. So I need to install both versions on my laptop. So how to handle different JAVA versions for different projects on the same machine?
Use SDKMAN https://sdkman.io/. That can help you to solve this issue.
You can give commands like:
sdk use java 8.282.08.1-amzn
or
sdk use java 11.0.10.hs-adpt
Each instance of JDK/JRE is installed into its own directory.
E.g. I have multiple JDK version in my /opt/java directory.
ls -1 /opt/java/
jdk-11.0.1
jdk1.8.0_171
openjdk-11.0.2
openjdk-14.0.1
I can switch between the versions by specifying full path to the java executable file.
E.g. running on java 11:
/opt/java/jdk-11.0.3/bin/java -jar my-springboot-app.jar
running on java 14:
/opt/java/openjdk-14.0.1/bin/java -jar my-springboot-app.jar
If you are using Unix-like system, you can also look at alternatives util. It helps to switch between different versions of applications (different java versions).
Each IDE is a separate let's say "ecosystem", and within that IDE you can set your ( in eclipse example ) java compiler and java build path java version.
Yes, you will need to install both of them on your machine, but there will be no collision between them if you set your working environment correctly within your IDEs.
The same would go for an example docker images.
If you fancy a terminal you can create a command that will switch for example MAVEN_HOME or JAVA_HOME to a specific JDK version
How to set JAVA_HOME in Linux for all users
Switching between different JDK versions in Windows
Each terminal has separate session so when you run your application on JDK8, open a new terminal, switch version, your other application will run without any issues on JDK11.
We are switching from Oracle JDK/JRE to OpenJDK. Now I found only the JDK but I want to have a JRE as well from OpenJDK. This is for installing our application on the clients without the need of having the full JDK.
Is there a way to create a JRE package from the OpenJDK for Windows X64?
Inspired by the article Using jlink to Build Java Runtimes for non-Modular Applications I used the commands:
java --list-modules to get a list of all openjdk modules available
jlink --no-header-files --no-man-pages --compress=2 --add-modules <module-list from step 1> --output java-runtime to create a compact jre.
For OpendJDK 12 this is the command I ended up with:
jlink --no-header-files --no-man-pages --compress=2 --add-modules java.base,java.compiler,java.datatransfer,java.desktop,java.instrument,java.logging,java.management,java.management.rmi,java.naming,java.net.http,java.prefs,java.rmi,java.scripting,java.se,java.security.jgss,java.security.sasl,java.smartcardio,java.sql,java.sql.rowset,java.transaction.xa,java.xml,java.xml.crypto,jdk.accessibility,jdk.aot,jdk.attach,jdk.charsets,jdk.compiler,jdk.crypto.cryptoki,jdk.crypto.ec,jdk.crypto.mscapi,jdk.dynalink,jdk.editpad,jdk.hotspot.agent,jdk.httpserver,jdk.internal.ed,jdk.internal.jvmstat,jdk.internal.le,jdk.internal.opt,jdk.internal.vm.ci,jdk.internal.vm.compiler,jdk.internal.vm.compiler.management,jdk.jartool,jdk.javadoc,jdk.jcmd,jdk.jconsole,jdk.jdeps,jdk.jdi,jdk.jdwp.agent,jdk.jfr,jdk.jlink,jdk.jshell,jdk.jsobject,jdk.jstatd,jdk.localedata,jdk.management,jdk.management.agent,jdk.management.jfr,jdk.naming.dns,jdk.naming.rmi,jdk.net,jdk.pack,jdk.rmic,jdk.scripting.nashorn,jdk.scripting.nashorn.shell,jdk.sctp,jdk.security.auth,jdk.security.jgss,jdk.unsupported,jdk.unsupported.desktop,jdk.xml.dom,jdk.zipfs --output java-runtime
As others have mentioned, there's no longer a separate JRE distributed with the JDK since Java 9. You will need to use jlink and specify the modules your code depends on to generate a custom jre.
Because this can be a hassle, I've created a web-based tool to make it easier to create a custom JRE from an OpenJDK implementation (such as Oracle HotSpot, Eclipse OpenJ9, or Amazon Corretto) using jlink. The tool will give you the correct jlink command to run depending on your needs.
I've also included a way to make a standard Java SE JRE for those who just want a basic lightweight (~40-60 MB) JRE. If you know how to use a terminal, it'll take you less than 2 minutes to create a general-use JRE for JDK 9 and up.
Give it a try here - EasyJRE: https://justinmahar.github.io/easyjre/
Amazon Corretto OpenJDK https://aws.amazon.com/corretto/ has the builds for JDK and JRE
So I'm going to post something a little bit easier than what was posted by SteinarH. I didn't want to have to compile that list myself so.... this does it for you. Also for the sense of being a bit more concise I wouldn't label it java-runtime but instead jre-11 (or whatever version you are using).
This is PowerShell:
jlink --no-header-files --no-man-pages --compress=2 --add-modules $($(java --list-modules) -join "," -replace "#[0-9]*") --output jre-11
According to the Building OpenJDK document1:
Windows XP is not a supported platform, but all newer Windows should be able to build OpenJDK.
It then goes on to explain that Cygwin is required to do the build, the requirements for native compilers and libraries, and the issue of the "bootstrap" JDK that is required to compile the Java classes in the source tree.
But the clear implication is that you can build OpenJDK on Windows and for Windows ... even though the end result is not supported by Oracle or the OpenJDK project.
Note that the build document describes the make targets for creating JRE and JDK "images". I think it is saying that these are binary trees that can be copied to a target system and used. You could create ZIPs from them ...
But a simpler approach is to use "jlink" to generate a JRE-like executable; see the accepted answer.
#Andrew Henle points out that there are costs and (if you put yourself in the mindset of a corporate lawyer) risks in rolling your own JRE. Whether you just use it internally or you provide it to customers. If this is a concern, you are in a bit of a bind:
From Java 9 onwards, Oracle does not ship JRE distributions at all. Not for Oracle Java. Not for OpenJDK Java. As far as Oracle is concerned, JREs end after Java 8.
Anything that you build for yourself is a cost and a (erm) risk.
Fortunately, there are 3rd-party vendors who ship JRE distributions for Java on Windows. (Both AdoptOpenJDK and Azul do at the time of writing).
Alternatively, just use an Oracle JDK distro. Disk space is cheap, networks are fast.
1 - That link is for the Java 9 version of the document. For others, you should be able to find a corresponding "building.html" document at the same place in the source tree.
Since Java 9, you can use jlink to create a custom runtime environment for your application, using only the modules you actually need to run, which is typically even smaller than the traditional JRE was.
I'm using openjdk 11 in place of jre8 since oracle announced the license change. My customers were unhappy about them changing the agreement.
To get it to work, all I had to do was rename the sdk folder to jre.
One problem I did have was an external library dll. where open jdk complained it could no longer find in the class path. To fix that I just copied the dlls to the system32 folder.
Hope this helps
Stuart
On this site you can get jdk and jre (the jdk contains jre)
https://adoptopenjdk.net/upstream.html.
But if you need to build a jre you can use the following code in python (I have taken the answer from #SteinarH), the code assumes that you are in the jdk bin and that there is no directory called jre at the previous level.
import os
jmod_str = os.popen('java --list-modules').read()
init = jmod_str.index('#')
end = jmod_str.index('\n')
version = jmod_str[init:end]
jmod_list = jmod_str.replace(version, '').replace('\n', ',')
jmod_list = jmod_list[:-1] if jmod_list[-1] == ',' else jmod_list
cmd = 'jlink --no-header-files --no-man-pages --compress=2 --module-path ..\jmods --add-modules '+ jmod_list + ' --output ..\jre'
As far as I know the only place you can download OpenJDK for Windows is Azul website. However, they only seem to provide full JDK, so if you want just the JRE you need to build it yourself as Stephen C suggested.
For a more straightforward approach i wrote this little tool, which you can use under Windows:
https://github.com/g3t00ls/OpenJDKtoOpenJRE
I personally use OpenJDK from:
https://jdk.java.net/
It basicly does exactly what SteinarH wrote.
Currently it includes all java modules and exludes all jdk modules! A GUI to select required modules / an auto detect function for required modules for even smaller JRE's will probably be added soon!
Currently it still needs jlink, so only >=v9 JDK's will work! This could change in the future!
Reasons for making another answer:
I needed a single line to make a standard JRE to put in my Windows installer
I didn't want to have to update it when I upgrade java
Method:
I back engineered the output from the page that Justin made: https://stackoverflow.com/a/54997476/1280293 (Excellent utility)
I took the output of java --list-modules
selected only lines that start with java
removed the #versionnumber from the end of each line
joined the array into a comma separated string
appended it to jlink --output jre --compress=2 --no-header-files --no-man-pages --module-path ../jmods --add-modules
Notes:
This command assumes you have added your java bin to your path
This creates it's output directory in the folder you run the command from
PowerShell:
jlink --output jre --compress=2 --no-header-files --no-man-pages --module-path ../jmods --add-modules "$((java --list-modules | Select-String -Pattern '^(java[^#]+?)#' | % {"$($_.Matches.Groups[1].value)"}) -join ',')"
Azul Systems provides up-to date Windows JREs.
Here the link to Java 18 Windows JRE:
https://www.azul.com/downloads/?os=windows&architecture=x86-64-bit&package=jre
Amazon Corretto nor AdoptOpenJDK provide Windows JREs.
We are using the Azul distribution since Oracle decided to change its licensing and made very good experience.
Also previous versions can be found:
I'm trying to install JDK8 on Debian Stretch. The recommended way is to use JavaPackage.
I have successfully packaged JDK6 and JDK7 using this method:
Download the JDK archive from Oracle
fakeroot make-jpkg jdk-7u55-linux-x64.tar.gz
dpkg -i the-resulting.deb
I can successfully create a .deb from the JDK8 archive, but when I install it with dpkg I'm missing a lot of dependencies.
gnome-icon-theme gtk-update-icon-cache java-common libasound2 libasound2-data libatk1.0-0 libatk1.0-data libcroco3 libdrm-amdgpu1 libdrm-intel1 libdrm-nouveau2 libdrm-radeon1 libdrm2 libgail-common libgail18 libgl1-mesa-dri libgl1-mesa-glx libglapi-mesa libgtk2.0-0 libgtk2.0-bin libgtk2.0-common libllvm3.9 libpciaccess0 librsvg2-2 librsvg2-common libtxc-dxtn-s2tc libx11-xcb1 libxcb-dri2-0 libxcb-dri3-0 libxcb-glx0 libxcb-present0 libxcb-sync1 libxcomposite1 libxcursor1 libxdamage1 libxfixes3 libxi6 libxinerama1 libxrandr2 libxshmfence1 libxtst6 libxxf86vm1 x11-common
I can install them manually but I'm not sure why I didn't have this dependency problem with the earlier JDKs. I'm writing an install script and it would please me to only install a single .deb rather than having to install all the extra dependencies separately.
make-jpkg supports JDK8 according to its man page.
make-jpkg builds a Debian package from the given Java distribution FILE.
Supported java binary distributions currently include:
* Oracle (http://www.oracle.com/technetwork/java/javase/downloads) :
- The Java Development Kit (JDK), version 6, 7 and 8
- The Java Runtime Environment (JRE), version 6, 7 and 8
- The Java API Javadoc, version 6, 7 and 8
(Choose tar.gz archives or self-extracting archives, do _not_ choose the RPM!)
Can anyone provide some insight as to why the .deb's created from earlier JDKs don't require any extra dependencies. Or perhaps it's just a case of their dependencies already existing in a stock Debian install.
Edit: I found this thread at Server Fault which goes some way to explaining it:
The reason this happens is that you are building a deb package from a binary distribution, i.e. a precompiled JDK. Usually, Debian packages are built from source, not from binaries. In order to do so, the person building the package would add all libraries the source depends on to a certain file (debian/control). Without those libraries installed, the source cannot be compiled and therefore would not result in a package.
My Java applet only supports 1.4 java run time(1). I am having one machine on which both Java 1.4 and 1.6 environment is installed. Is there some setting available by which I can make sure my applet will always use Java 1.4 run time when it runs?
We are using key event class private data array bData with the help of Java reflection. The data which is there in this array JDK 1.4 and 1.6 is different in both the version.
A Java application compiled with JDK 1.4 will run on JDK 1.6.
You can compile a Java application with JDK 1.6, but compatible with JDK 1.4 by configuring the 'source level'.
Although you can choose your default JDK to be safe, but it depends on your operating system. If you are on Linux, you can choose between available Java versions using pdate-alternatives --config java command (which will modify some symlinks in the hindsight).
On Windows 7:
Control Panel -> Programs -> Java
Select 'Java' tab, and View the Java Runtime Environment settings.
Ensure that your Java 1.4 entry is selected.
There's a way to force a specific installed version to run, but if one Java plugin replaces the other there might be an issue with this. See linked question for further details.
Force Internet Explorer to use a specific Java Runtime Environment install?
Are there any issues with running the 1.4 code on 1.6? If not, you should be fine. Just avoid using anything in the classpath that changed significantly between these versions. Otherwise, look [here][1]. The codebase download thing is interesting, since it lets you download a different classpath. So, regardless of the JRE version, you could force the download of a 1.4 JRE classpath, which should ensure full compatability.
Edit: found an updated guide to using previous classpaths with newer Java versions in applets, which actually seems to work:
http://download.oracle.com/javase/tutorial/deployment/applet/deployingApplet.html
Edit 2: I actually have it working, but it appears to need to download JRE 1.4 and install it, but then it will run the applet with it automatically. However, this might be suitable for your needs.
http://www.2shared.com/file/bl3Rua2e/applet.html -- extract the archive, and then run index.html inside this. All source code is included.
We have a couple of applications running on Java 5 and would like now to bring in an application based on Java 6. Can both java versions live together under Windows?
Is there any control panel to set the appropriate Java version for different applications, or any other way to set up, what version of Java will be used to run that particular application?
Of course you can use multiple versions of Java under Windows. And different applications can use different Java versions. How is your application started? Usually you will have a batch file where there is something like
java ...
This will search the Java executable using the PATH variable. So if Java 5 is first on the PATH, you will have problems running a Java 6 application. You should then modify the batch file to use a certain Java version e.g. by defining a environment variable JAVA6HOME with the value C:\java\java6 (if Java 6 is installed in this directory) and change the batch file calling
%JAVA6HOME%\bin\java ...
I was appalled at the clumsiness of the CLASSPATH, JAVA_HOME, and PATH ideas, in Windows, to keep track of Java files. I got here, because of multiple JREs, and how to content with it. Without regurgitating information, from a guy much more clever than me, I would rather point to to his article on this issue, which for me, resolves it perfectly.
Article by: Ted Neward: Multiple Java Homes: Giving Java Apps Their Own JRE
With the exponential growth of Java as a server-side development language has come an equivablent
exponential growth in Java development tools, environments, frameworks, and extensions.
Unfortunately, not all of these tools play nicely together under the same Java VM installation. Some
require a Servlet 2.1-compliant environment, some require 2.2. Some only run under JDK 1.2 or above,
some under JDK 1.1 (and no higher). Some require the "com.sun.swing" packages from pre-Swing 1.0
days, others require the "javax.swing" package names.
Worse yet, this problem can be found even within the corporate enterprise, as systems developed using
Java from just six months ago may suddenly "not work" due to the installation of some Java Extension
required by a new (seemingly unrelated) application release. This can complicate deployment of Java
applications across the corporation, and lead customers to wonder precisely why, five years after the
start of the infamous "Installing-this-app-breaks-my-system" woes began with Microsoft's DLL schemes,
we still haven't progressed much beyond that. (In fact, the new .NET initiative actually seeks to solve the
infamous "DLL-Hell" problem just described.)
This paper describes how to configure a Java installation such that a given application receives its own,
private, JRE, allowing multiple Java environments to coexist without driving customers (or system
administrators) insane...
It is absolutely possible to install side-by-side several JRE/JDK versions. Moreover, you don't have to do anything special for that to happen, as Sun is creating a different folder for each (under Program Files).
There is no control panel to check which JRE works for each application. Basically, the JRE that will work would be the first in your PATH environment variable. You can change that, or the JAVA_HOME variable, or create specific cmd/bat files to launch the applications you desire, each with a different JRE in path.
We can install multiple versions of Java Development kits on the same machine using SDKMan.
Some points about SDKMan are as following:
SDKMan is free to use and it is developed by the open source community.
SDKMan is written in bash and it only requires curl and zip/unzip programs to be present on your system.
SDKMan can install around 29 Software Development Kits for the JVM such as Java, Groovy, Scala, Kotlin and Ceylon. Ant, Gradle, Grails, Maven, SBT, Spark, Spring Boot, Vert.x.
We do not need to worry about setting the _HOME and PATH environment variables because SDKMan handles it automatically.
SDKMan can run on any UNIX based platforms such as Mac OSX, Linux, Cygwin, Solaris and FreeBSD and we can install it using following commands:
$ curl -s "https://get.sdkman.io" | bash
$ source "$HOME/.sdkman/bin/sdkman-init.sh"
Because SDKMan is written in bash and only requires curl and zip/unzip to be present on your system. You can install SDKMan on windows as well either by first installing Cygwin or Git Bash for Windows environment and then running above commands.
Command sdk list java will give us a list of java versions which we can install using SDKMan.
Installing Java 8
$ sdk install java 8.0.201-oracle
Installing Java 9
$ sdk install java 9.0.4-open
Installing Java 11
$ sdk install java 11.0.2-open
Uninstalling a Java version
In case you want to uninstall any JDK version e.g., 11.0.2-open you can do that as follows:
$ sdk uninstall java 11.0.2-open
Switching current Java version
If you want to activate one version of JDK for all terminals and applications, you can use the command
sdk default java <your-java_version>
Above commands will also update the PATH and JAVA_HOME variables automatically. You can read more on my article How to Install Multiple Versions of Java on the Same Machine.
It should be possible changing setting the JAVA_HOME environment variable differently for specific applications.
When starting from the command line or from a batch script you can use set JAVA_HOME=C:\...\j2dskXXX to change the JAVA_HOME environment.
It is possible that you also need to change the PATH environment variable to use the correct java binary. To do this you can use set PATH=%JAVA_HOME%\bin;%PATH%.
I use a simple script when starting JMeter with my own java version
setlocal
set JAVA_HOME="c:\java8"
set PATH=%JAVA_HOME%\bin;%PATH%;
java -version
To have a java "portable"
you can use this method here:
https://www.whitebyte.info/programming/java/how-to-install-a-portable-jdk-in-windows-without-admin-rights
Or use links. While it is rather unpleasant to update the PATH in a running environment, it's easy to recreate a link to a new version of JRE/JDK. So:
install different versions of JDK you want to use
create a link to that folder either by junction or by built-in mklink command
set the PATH to the link
If other version of java is to be used, delete the link, create a new one, PATH/JAVA_HOME/hardcoded scripts remain untouched
Invoking Java with "java -version:1.5", etc. should run with the correct version of Java. (Obviously replace 1.5 with the version you want.)
If Java is properly installed on Windows there are paths to the vm for each version stored in the registry which it uses so you don't need to mess about with environment versions on Windows.
If you use Java Web Start (you can start applications from any URL, even the local file system) it will take care of finding the right version for your application.
Using Java Web Start, you can install multiple JRE, then call what you need.
On win, you can make a .bat file:
1- online version:
<your_JRE_version\bin\javaws.exe> -localfile -J-Djnlp.application.href=<the url of .jnlp file.jnlp> -localfile -J "<path_temp_jnlp_file_.jnlp>"
2- launch from cache:
<your_JRE_version\bin\javaws.exe> -localfile -J "<path_of_your_local_jnlp_file.jnlp>"