if the compile-output shows something like:

Recompile with -Xlint:deprecation for details

Then it is time to get to the details of this message:

in Gradle-scripts/build.gradle (Project) include the following line(s):

tasks.withType(JavaCompile) {
        options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation"
    }

When you now run the app the root-cause is shown in the output:

Done