Run lein with different JVM

lein-different-jvm.sh

#!/bin/bash

JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents/Home lein run

Also set permanently in ~/.lein/profiles.clj:

{:user {:java-cmd "/Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents/Home/bin/java"}}

Download Java 7 JDK from http://www.oracle.com/technetwork/java/javase/downloads/java-archive-downloads-javase7-521261.html

JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents/Home \
JAVA_TOOL_OPTIONS='-XX:+CMSClassUnloadingEnabled -XX:+UseConcMarkSweepGC -XX:MaxPermSize=256m' \
lein run

Download OpenJDK 7 at http://download.cnet.com/OpenJDK-7-for-OS-X-Lion/3001-2213_4-75609826.html

Actually apparently OpenJDK is already included here:

 /Applications/Xcode.app/Contents/Applications/Application\ Loader.app/Contents/MacOS/itms/java/bin/java

So:

JAVA_HOME='/Applications/Xcode.app/Contents/Applications/Application Loader.app/Contents/MacOS/itms/java' \
JAVA_TOOL_OPTIONS='-XX:+CMSClassUnloadingEnabled -XX:+UseConcMarkSweepGC -XX:MaxPermSize=256m' \
lein run

lein version to double-check JAVA_HOME worked correctly

Use Java 8:

JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_141.jdk/Contents/Home lein run

# to run things like JARs
alias java=$JAVA_HOME/bin/java

Note : I couldn't use JAVA_HOME, had to use JAVA_CMD

JAVA_CMD=/home/jerome/bin/jdk1.8.0_131/bin/java lein -v
Leiningen 2.9.1 on Java 1.8.0_131 Java HotSpot(TM) 64-Bit Server VM

@jprudent I've been using Jabba (https://github.com/shyiko/jabba) for this stuff now

Is it possible to set JVM version per project, for example via project.clj?

Edit: I discovered how to do this with jEnv, using jenv local <jvm-version> within my project directory. I suppose that does the trick! Although it would still be useful to do this in project.clj, add to source control, etc.

Is it possible to set JVM version per project, for example via project.clj?

you can, add
:java-cmd "/Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents/Home/bin/java"
to your project.clj, or the path of whatever other java binary you are using