I've been working with Java for a bit now and the JDK/JRE version has given me quite a bit of trouble lately. I am developing using the Intellij IDEA IDE and it of course uses the latest version of the JDK, 14. However when I attempt to execute software compiled with JDK 14 outside the IDE, I get an error that the JRE isn't new enough to run this software. So I updated Java on my computer and another machine and attempt to run again without any success. After some digging, I tweaked my machine to use the JRE included in the JDK 14 which is compatible.
However it is kind of odd that I had to do that, one would think that the latest version of java should of been enough to run applications made with the latest version of the JDK (14). Right now Java is version 8 build 251 and says there is no newer update available. If JDK 14 is out for a while now, why would they not update the version of Java they ship?
The problem is partially solved, as only the machine I am using for development is capable of executing the created applications. Other people I've sent them to have been unable to run them, despite having the latest version of java. Also it is a pain to get the latest JDK, especially when having limited experience on how to get rid of old versions, change path point to the latest version, get the right package (open/oracle JDK) and do that for windows and several distrubutions of linux. What is going on? Did I get Java from the wrong place and everyone else as well? Why are oracle doing this and why are there no java updates since clearly there exists a newer version?
Starting with Java-11, separate JRE does not exist anymore. In other words, if you are using Java-11 or above, you should care about JDK only.
You should uninstall JRE-8 from your machine and make sure your JDK-14 bin folder in the PATH variable. Some application even requires JAVA_HOME to work and therefore you should make sure that your system has an environment variable called JAVA_HOME and its value set to the root folder of JDK-14 (i.e. one level above your JDK bin).
Q: What should my clients do to run my application compiled on JDK-14?
Ans: Your clients must install JDK-14. Also, check this thread for some alternatives.
You're confusing how IntelliJ or JDK are used on the OS. IntelliJ, now, often comes with its JDK binaries (but even this can be configured, IntelliJ can be configured to use any JDK/JRE build you'll provide to it); however, if you run your Java application out of IntelliJ, most likely you're using Java installed locally on your OS, which might be referenced via your JAVA_HOME environment variable.
I'd suggest to:
Check java -version in your shell (and hence you'll see what JVM instance your OS spins up when you run a Java application);
Check where java (on Windows, or which - on Linux) in your shell, to see all the Java binaries available on your OS.
Try to uninstall Java SE Development Kit and Java JRE(if you have both in your machine) and reinstall both again, JDK and JRE both, I am sharing my google drive link where you can find the latest version of both JDK and JRE and when you are done installing, add there bin folder path in the Environment Variables of your machine.
I have Java 8 and Java 9 installed on my system (not via Homebrew).
I have my JAVA_HOME env variable setup to point to Java 8 (in my .profile) and I can successful compile programs that require Java 8.
However I'm trying to install a program that also requires Java 8 via Homebrew, but it keeps failing - seemingly because it's trying to build it with Java 9.
Is there a way I can tell Homebrew to only build using Java 8?
Looking at the logs for the failed install strongly suggests Homebrew is trying to use Java 9 (its CFLAGS and PATH include references to "jdk-9", etc.). Where does Homebrew get its environment settings from?
Thanks in advance!
I have a web Application and i need to upgrade java jre version from 6 to 7 .I am using Eclipse as IDE.I tried to update the Jre from eclipse .I have even updated the JAVA_HOME environment variable but i am getting following error
C:\Program Files\Java\jdk1.7.0_55\jre..\lib\tools.jar
Please ensure you are using JDK 1.4 or above and
not a JRE (the com.sun.tools.javac.Main class is required).
In most cases you can change the location of your Java
installation by setting the JAVA_HOME environment variable.
Thanks
Download java hereand install it as a common application.
Then in Eclipse use Window->Prefrences->Java->Installed JREs
#Roman Bondar I guesss OP wanted to know more than just the setting.
Basically, JREs are meant to be downwards compatible, so that you are able to execute java classes compiled with version 6 with a runtime from java 7.
But as always, there may be special cases when things have to be changed, e.g. container or libraries. I remember a case back when I migrated to java 6 that it required a special version of JBoss.
Check out this Oracle blog as a starting point.
I've been using Java on OS X for many, many years and recently when Apple stopped including Java by default I let the OS go and install it for me (Apple's variety, of course).
So now I'm using OS X 10.8 and I need to install Java 7 so I just got Oracle's Update 15 in DMG form and ran the installer. It updated my /usr/bin/java (and related files) to point here:
/System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java
Tracing this back to '/System/Library/Frameworks/JavaVM.framework/Versions' everything either points to 'Current' or 'CurrentJDK', the former being a link to 'A' (which is Oracle's Java 7, from what I can tell, not sure why it is 'A') and the latter being a link to Apple's Java 6 in '/System/Library/Java/JavaVirtualMachines/1.6.0.jdk'.
Now this is all really confusing but this isn't even my question yet. It appears there is a Java 7 installed here:
/System/Library/Frameworks/JavaVM.framework/Versions/A
But there is also a Java 7 installed here:
/Library/Java/JavaVirtualMachines/jdk1.7.0_15.jdk
Finding 'java' in both and printing out the version yields the same version and build (java version "1.7.0_15"), however, when hashing the files they are different.
So does this mean Oracle installed Java 7 in two different places? If so, why? Which am I supposed to use? And why do some things still point to Java 6 (CurrentJDK).
I've looked on Oracle's website but nothing there clears anything up.
Oracle's JVM is only installed in one location. You've been misled!
As you've noted, the Java commands in /usr/bin are symlinks to binaries in /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands. The binaries within that directory are stub applications that determine which Java VM to use*, and then exec the corresponding real binary within that VM version. This is why all of the binaries within /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands are almost identical in size, despite the fact that you'd expect them to be implementing quite different functionality.
You can see this in action by using dtrace:
mrowe#angara:~$ sudo dtrace -n 'syscall::posix_spawn:entry { trace(copyinstr(arg1)); }' -c "/usr/bin/java -version"
dtrace: description 'syscall::posix_spawn:entry ' matched 1 probe
dtrace: pid 44727 has exited
CPU ID FUNCTION:NAME
8 619 posix_spawn:entry /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/java
The given dtrace invocation prints out the path argument to posix_spawn when it is called by java -version. In my case the stub application has found Apple's Java 1.6 runtime in /System/Library/Java/JavaVirtualMachines/1.6.0.jdk and is invoking that version of the java command.
The stub binaries also have another benefit: when they detect that no Java VM is installed they will prompt the user to install one.
As for the CurrentJDK symlink, as best as I can tell this for sake of backwards-compatibility with the past when Apple was the only source of the JVM on OS X.
* A combination of factors are considered when determining which Java VM should be used. JAVA_HOME is used if set (try JAVA_HOME=/tmp java). If JAVA_HOME is not set then the list of all virtual machines on the system is discovered. The JAVA_VERSION and JAVA_ARCH environment variables are used, if set, to filter the list of virtual machines to a particular version and supported architecture. The resulting list is then sorted by architecture (preferring 64-bit over 32-bit) and version (newer is better), and the best match is returned.
The Oracle Java 7 JRE (i.e. the one that is used by the web browser plugin to run applets and Java Web Start) installs itself in /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home, and it is this one that any automatic updates will affect. The JDK (the one you download from http://www.oracle.com/technetwork/java/javase/downloads/index.html) installs by creating a directory under /Library/Java/JavaVirtualMachines, and it's up to you to update this yourself. You can have multiple JDK versions installed side by side but only one "public" JRE under JavaAppletPlugin.plugin (which will correspond to the latest installed JDK or a later version if it has been auto-updated since).
As explained by bdash, the commands under /usr/bin are stubs that delegate to whichever JDK/JRE is pointed to by the JAVA_HOME environment variable, or if that is not set then they will pick the most appropriate Java to run. You can use /usr/libexec/java_home to see which one the stubs would pick. If no Java is installed the stubs will offer to install the latest Apple Java 6 (as far as I know they will not offer to install Java 7).
I find this post:
https://developer.apple.com/library/mac/qa/qa1170/_index.html
The /usr/libexec/java_home tool dynamically finds the top Java version specified in Java Preferences for the current user.
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>"