Too many classes in --main-dex-list, main dex capacity exceeded with javafxports-plugin - javafxports

Question

I am trying to make my application run on an android device by using the jfxmobile-plugin.
When I do a
gradle android
on my project I get
Execution failed for task ':dex'.
> UNEXPECTED TOP-LEVEL EXCEPTION:
com.android.dex.DexException: Too many classes in --main-dex-list, main dex capacity exceeded
at com.android.dx.command.dexer.Main.processAllFiles(Main.java:546)
at com.android.dx.command.dexer.Main.runMultiDex(Main.java:366)
at com.android.dx.command.dexer.Main.run(Main.java:275)
at com.android.dx.command.dexer.Main.main(Main.java:245)
at com.android.dx.command.Main.main(Main.java:106)
My gradle file is this
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'org.javafxports:jfxmobile-plugin:1.3.2'
}
}
apply plugin: 'org.javafxports.jfxmobile'
mainClassName = 'de.package.of.application.ClientApp'
dependencies {
compile 'com.annimon:stream:1.0.1'
compile 'com.jakewharton.threetenabp:threetenabp:1.0.4'
compile 'com.gluonhq:charm:4.2.0'
androidRuntime 'com.gluonhq:charm-android:3.0.0'
iosRuntime 'com.gluonhq:charm-ios:3.0.0'
desktopRuntime 'com.gluonhq:charm-desktop:3.0.0'
compile fileTree(dir: 'target/dependencies', include: '*.jar')
runtime fileTree(dir: 'target/dependencies', include: '*.jar')
}
repositories {
jcenter()
maven {
url 'http://nexus.gluonhq.com/nexus/content/repositories/releases'
}
}
jfxmobile {
ios {
forceLinkClasses = ['ensemble.**.*']
}
android {
//manifest = 'AndroidManifest.xml'
compileSdkVersion = '24'
androidSdk='C:/Tools/android-sdk-windows'
packagingOptions {
exclude 'META-INF/DEPENDENCIES.txt'
exclude 'META-INF/LICENSE.txt'
exclude 'META-INF/NOTICE.txt'
exclude 'META-INF/NOTICE'
exclude 'META-INF/LICENSE'
//... some more excludes
}
dexOptions {
javaMaxHeapSize '3g'
// keepRuntimeAnnotatedClasses false
}
}
}
I found some similar questions about the exception logged by the gradle build but non brought a real solution for me so far especially in combination with the usage of the javafxports-plugin.
Some suggested to set the compileSdkVersion to a minumum of 21-> I
use 24 -> this does not help.
Using keepRuntimeAnnotatedClasses=false is not an option because the
application is build on some Reflection/injection-logic
(spring-framework).
As I understand the build process takes those classes into account to
put in the main-dex-file which are required to initially start up the
application. So I stripped down the application to an absolut minimum
with no other dependencies (direct or transitive) to the other
libraries of my application (no imports of classes from other
libraries, except to java/javafx). The other libraries are
included by the 'runtime fileTree...' part of the gradle-file but
are not really used at startup. Idea was to create a 2-phase
startup of the application: First a minimum-app and then, when
the minimum app is loaded, start the real application code. -> no
success, it seems all libraries are taken into account for the
main-dex-file.
I do not see how to solve it together with javafxports. Does anyone have suggestions?