I found a solution:
def platformSources() {
return files(’…/platform/src/main/java’, ‘…/platform/src/main/resources’)
}
and then include “platformSources” into the GWT classpath:
classpath {
[
sourceSets.main.java.srcDirs,
// Java source
sourceSets.main.output.resourcesDir,
// Generated resources
sourceSets.main.output.classesDir,
// Generated classes
sourceSets.main.compileClasspath,
// Deps
platformSources()
]
}