How to specify Java Source and Target Compatibility in a Gradle multi project
I have a multiple project setup and I want to build top level projects using different JDKs.
I did some experiments by myself and the following configuration worked for me
(using gradle 3.1 and the wrapper function).
At the root level my gradle.properties file looks like this:
org.gradle.daemon=true JDK7_HOME=/usr/lib/jvm/jdk-7-oracle-x64 JDK8_HOME=/usr/lib/jvm/oracle-java8-jdk-amd64
Default JDK should be JDK 7. So I defined this in my root build.gradle file
...
subprojects {
apply plugin: 'java'
sourceCompatibility = 1.7
targetCompatibility = 1.7
compileJava.doFirst {
println 'source compatibility: ' + sourceCompatibility
println 'targetCompatibility: ' + targetCompatibility
}
tasks.withType(JavaCompile) {
if (project.hasProperty('JDK7_HOME')) {
options.fork = true
options.bootClasspath = '$JDK7_HOME/jre/lib/rt.jar:$JDK7_HOME/jre/lib/jce.jar'
}
}
test.doFirst {
println 'executing tests with JDK ' + test.executable
}
tasks.withType(Test) {
if (project.hasProperty('JDK7_HOME')) {
test.executable = '$JDK7_HOME/bin/java'
}
}
...
}
...
With this configuration the source and target compatibility is now set to 1.7 for every
sub project. I use compileJava.doFirst and test.doFirst to verify that everything works as expected.
Now, in my sub project B I want to use Java 8. The following did the trick:
build.gradle
...
tasks.withType(JavaCompile) {
if (project.hasProperty('JDK8_HOME')) {
sourceCompatibility = 1.8
targetCompatibility = 1.8
options.fork = true
options.bootClasspath = '$JDK8_HOME/jre/lib/rt.jar:$JDK8_HOME/jre/lib/jce.jar';
}
}
tasks.withType(Test) {
if (project.hasProperty('JDK8_HOME')) {
test.executable = '$JDK8_HOME/bin/java'
}
}
...
That it’s. I hope this has helped you.
If not, please check these ones:
http://stackoverflow.com/questions/21028438/gradle-sourcecompatibility-has-no-effect-to-subprojects