How to change java version used by cordova subprojects

Question

I have a Cordova project, and I am building a android plugin for it. My plugin then uses a library that uses the diamond operation (<>). I tried to run it but I receive this error :

diamond operator is not supported in -source 1.6
    ArrayList<Node> selectedProviders = new ArrayList<>();
                                                      ^
  (use -source 7 or higher to enable diamond operator)

When I run:

$ java -version
java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)
$ javac -version
javac 1.7.0_67

I research before posting and some people resolved by changing the ant config.xml to

<property name="java.target" value="1.7" />
<property name="java.source" value="1.7" />

But it didnt worked for me.

I also tried make a build-extra-gradle file to set-up the sourceCompatibility and targetCompatibility, but it just appears to resolve the main project, not the subproject that I use on my plugin.

Answer 1

Okay, what worked for me was adding all the sub-projects(libraries) that you plugin uses as main-libraries of yout cordova project.

Here what I did: Copy all the libraries to libs, go to eclipse>build path>order and export>Mark everything. After that, you have to create a build-extras.gradle file on your root/platforms/android folder. Put this code on your file:

ext.postBuildExtras = {
android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
    allprojects {
        compileOptions {
            sourceCompatibility = JavaVersion.VERSION_1_7
            targetCompatibility = JavaVersion.VERSION_1_7
        }
    }
}
}

Keeping referencing in the subprojects, though. You have to make the reference from the project and the subproject (not sure why, but worked.).