Mac OS X and multiple Java versions

问题

How can I install an additional java on MacOS? I installed jdk8 and that works fine. but now I need a jdk7 installation for development purposes. When trying to install the old version via DMG file, i get a warning, that there is already a newer version of java installed and the installer quits.

/usr/libexec/java_home -verbose
Matching Java Virtual Machines (1):
    1.8.0_20, x86_64:   \"Java SE 8\" /Library/Java/JavaVirtualMachines/jdk1.8.0_20.jdk/Contents/Home

   /Library/Java/JavaVirtualMachines/jdk1.8.0_20.jdk/Contents/Home

How to install jdk7 in addition to this one?

Thanks
Dakky

回答1:

The cleanest way to manage multiple java versions on Mac is to use Homebrew.

And within Homebrew, use:

homebrew-cask to install the versions of java
jenv to manage the installed versions of java

As seen on http://hanxue-it.blogspot.ch/2014/05/installing-java-8-managing-multiple.html , these are the steps to follow.

install homebrew
install homebrew jenv
install homebrew-cask
install a specific java version using cask (see "homebrew-cask versions" paragraph below)
add this version for jenv to manage it
check the version is correctly managed by jenv
repeat steps 4 to 6 for each version of java you need

homebrew-cask versions

Add the homebrew/cask-versions tap to homebrew using:

brew tap homebrew/cask-versions

Then you can look at all the versions available:

brew search java

Then you can install the version(s) you like:

brew cask install java7
brew cask install java6

And add them to be managed by jenv as usual.

jenv add <javaVersionPathHere>

I think this is the cleanest & simplest way to go about it.

Another important thing to note, as mentioned in Mac OS X 10.6.7 Java Path Current JDK confusing :

For different types of JDKs or installations, you will have different paths

You can check the paths of the versions installed using /usr/libexec/java_home -V, see How do I check if the Java JDK is installed on Mac?

On Mac OS X Mavericks, I found as following:

1) Built-in JRE default: /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin/Contents/Home

2) JDKs downloaded from Apple: /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/

3) JDKs downloaded from Oracle: /Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home

Resources

Removing Java 8 JDK from Mac
http://hanxue-it.blogspot.ch/2014/05/installing-java-8-managing-multiple.html
http://sourabhbajaj.com/mac-setup/index.html
http://brew.sh
https://github.com/Homebrew/homebrew/tree/master/share/doc/homebrew#readme
http://sourabhbajaj.com/mac-setup/Homebrew/README.html
"brew tap” explained https://github.com/Homebrew/homebrew/blob/master/share/doc/homebrew/brew-tap.md
“brew versions” explained Homebrew install specific version of formula? and also https://github.com/Homebrew/homebrew-versions
https://github.com/caskroom/homebrew-cask
“cask versions”, similar to “brew versions”, see https://github.com/caskroom/homebrew-versions and also https://github.com/caskroom/homebrew-cask/issues/9447
http://www.jenv.be
https://github.com/gcuisinier/jenv

回答2:

Uninstall jdk8, install jdk7, then reinstall jdk8.

My approach to switching between them (in .profile) :

export JAVA_7_HOME=$(/usr/libexec/java_home -v1.7)
export JAVA_8_HOME=$(/usr/libexec/java_home -v1.8)
export JAVA_9_HOME=$(/usr/libexec/java_home -v9)

alias java7='export JAVA_HOME=$JAVA_7_HOME'
alias java8='export JAVA_HOME=$JAVA_8_HOME'
alias java9='export JAVA_HOME=$JAVA_9_HOME'

#default java8
export JAVA_HOME=$JAVA_8_HOME

Then you can simply type java7 or java8 in a terminal to switch versions.

(edit: updated to add Dylans improvement for Java 9)

回答3:

For macOS Sierra 420

This guide was cobbled together from various sources (replies above as well as other posts), and works perfect.

0. If you haven't already, install homebrew.

See https://brew.sh/

1. Install jenv

brew install jenv

2. Add jenv to the bash profile

if which jenv > /dev/null; then eval "$(jenv init -)"; fi

3. Add jenv to your path

export PATH="$HOME/.jenv/shims:$PATH"

4. Tap "caskroom/versions"

FYI: "Tap" extends brew's list of available repos it can install, above and beyond brew's default list of available repos.

brew tap caskroom/versions

5. Install the latest version of java

brew cask install java

6. Install java 6 (or 7 or 8 whatever you need)

brew cask install java6
#brew cask install java7
#brew cask install java8

? Maybe close and restart Terminal so it sees any new ENV vars that got setup.

7. Review Installations

All Java version get installed here: /Library/Java/JavaVirtualMachines lets take a look.

ls -la /Library/Java/JavaVirtualMachines

8. Add each path to jenv one-at-a-time.

We need to add "/Contents/Home" to the version folder. WARNING: Use the actual paths on your machine... these are just EXAMPLE's

jenv add /Library/Java/JavaVirtualMachines/1.6.0___EXAMPLE___/Contents/Home
jenv add /Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk___EXAMPLE___/Contents/Home

9. Check if jenv registered OK

jenv versions

10. Set java version to use (globably)

Where XX matches one of the items in the versions list above.

jenv global XX

Check java version

java -version

Check jenv versions

Should also indicate the current version being used with an asterisk.

jenv versions

DONE

Quick future reference

To change java versions

... See the list of available java versions

jenv versions

... then, where XX matches an item in the list above

jenv global XX

回答4:

SDKMAN! is a great tool for using multiple versions of Java, Gradle, Groovy, Kotlin, and other JVM tools on Mac OS. Installation and usage doc are plainly on the main site.

(I have no affiliation, just a happy user).

As an example usage, if I type the following in a Terminal window, there is a list of available Java SDK versions (edited for brevity):

$ sdk list java
Available Java Versions
   + 9ea170                                                                        
 > + 8u131                                                                         
     7u141-zulu

Here + denotes that the version is installed. > denotes which version is currently in use. To install a version:

$ sdk install java 7u141-zulu

To use a version in this Terminal window:

$ sdk use java 9ea170

回答5:

As found on this website So Let’s begin by installing jEnv

Run this in the terminal

brew install https://raw.github.com/gcuisinier/jenv/homebrew/jenv.rb

Add jEnv to the bash profile

if which jenv > /dev/null; then eval "$(jenv init -)"; fi

When you first install jEnv will not have any JDK associated with it.

For example, I just installed JDK 8 but jEnv does not know about it. To check Java versions on jEnv

At the moment it only found Java version(jre) on the system. The * shows the version currently selected. Unlike rvm and rbenv, jEnv cannot install JDK for you. You need to install JDK manually from Oracle website.
Install JDK 6 from Apple website. This will install Java in /System/Library/Java/JavaVirtualMachines/. The reason we are installing Java 6 from Apple website is that SUN did not come up with JDK 6 for MAC, so Apple created/modified its own deployment version.
Similarly install JDK7 and JDK8.
Add JDKs to jEnv.

JDK 6:

JDK 7:

JDK 8:
Check the java versions installed using jenv
So now we have 3 versions of Java on our system. To set a default version use the command
```
jenv local <jenv version>
```
Ex – I wanted Jdk 1.6 to start IntelliJ
```
jenv local oracle64-1.6.0.65
```
check the java version

java -version

That’s it. We now have multiple versions of java and we can switch between them easily. jEnv also has some other features, such as wrappers for Gradle, Ant, Maven, etc, and the ability to set JVM options globally or locally. Check out the documentation for more information.

回答6:

I find this Java version manager called Jabba recently and the usage is very similar to version managers of other languages like rvm(ruby), nvm(node), pyenv(python), etc. Also it's cross platform so definitely it can be used on Mac.

After installation, it will create a dir in ~/.jabba to put all the Java versions you install. It "Supports installation of Oracle JDK (default) / Server JRE, Zulu OpenJDK (since 0.3.0), IBM SDK, Java Technology Edition (since 0.6.0) and from custom URLs.".

Basic usage is listed on their Github. A quick summary to start:

curl -sL https://github.com/shyiko/jabba/raw/master/install.sh | bash && . ~/.jabba/jabba.sh

# install Oracle JDK
jabba install 1.8 # "jabba use 1.8" will be called automatically  
jabba install 1.7 # "jabba use 1.7" will be called automatically 

# list all installed JDK's
jabba ls

# switch to a different version of JDK
jabba use 1.8

回答7:

I am using Mac OS X 10.9.5. This is how I manage multiple JDK/JRE on my machine when I need one version to run application A and use another version for application B.

I created the following script after getting some help online.

#!bin/sh
function setjdk() {
  if [ $# -ne 0 ]; then
   removeFromPath '/Library/Java/JavaVirtualMachines/'
   if [ -n "${JAVA_HOME+x}" ]; then
    removeFromPath $JAVA_HOME
   fi
   export JAVA_HOME=/Library/Java/JavaVirtualMachines/$1/Contents/Home
   export PATH=$JAVA_HOME/bin:$PATH
  fi
 }
 function removeFromPath() {
  export PATH=$(echo $PATH | sed -E -e "s;:$1;;" -e "s;$1:?;;")
 }
#setjdk jdk1.8.0_60.jdk
setjdk jdk1.7.0_15.jdk

I put the above script in .profile file. Just open terminal, type vi .profile, append the script with the above snippet and save it. Once your out type source .profile, this will run your profile script without you having to restart the terminal. Now type java -version it should show 1.7 as your current version. If you intend to change it to 1.8 then comment the line setjdk jdk1.7.0_15.jdk and uncomment the line setjdk jdk1.8.0_60.jdk. Save the script and run it again with source command. I use this mechanism to manage multiple versions of JDK/JRE when I have to compile 2 different Maven projects which need different java versions.

回答8:

Jenv on Mac Sierra:

if not working after install, do this bug fix to add java executable to path

export PATH="$HOME/.jenv/shims:$PATH"

even though eval "$(jenv init -)" could do this job. The reason is /bin folder is not there anymore as describe in it's homepage, but shim folder is used as /bin instead.

Make sure ~/.jenv is there
which java may print /Library/...
jenv global 1.8
jenv shell 1.8

Eventually, which java gives you:

/Users/xxxx/.jenv/shims/java

回答9:

Here's a more DRY version for bash (Based on Vegard's answer)

Replace 1.7 and 1.8 with whatever versions you are interested with and you'll get an alias called 'javaX'; where 'X' is the java version (7 / 8 in the snippet below) that will allow you to easily switch versions

for version in 1.7 1.8; do
    v="${version: -1}"
    h=JAVA_"$v"_HOME

    export "$h"=$(/usr/libexec/java_home -v $version)

    alias "java$v"="export JAVA_HOME=\$$h"
done

来源：https://stackoverflow.com/questions/26252591/mac-os-x-and-multiple-java-versions

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