$ tree common/ base/ app/
common/
├── build.gradle
└── src
    └── main
        └── java
            └── common
                └── MyLibrary.java
base/
├── build.gradle
└── src
    └── main
        └── java
            └── base
                ├── MyBase.java
                └── MyInterface.java
app/
├── build.gradle
└── src
    └── main
        └── java
            └── app
                ├── Main.java
                └── MyApp.java

$ ./gradlew build

$ ./gradlew :common:build

$ ./gradlew :app:customFatJar
$ java -jar app/build/libs/executable-1.0.jar
17:20:42.309 [main] INFO base.MyBase - called doSomeProcess in Base
17:20:42.310 [main] INFO common.MyLibrary - do some process
17:20:42.311 [main] INFO base.MyBase - log floor: 3
17:20:42.316 [main] INFO base.MyBase - f.getCumPct('Z'): 0.5

$ ./gradlew --info cleanTest test