create a fat jar in gradle

How to create a fat jar in a gradle build:

// this task builds a fat jar which includes the runtime dependencies in the jar
jar {
   dependsOn configurations.runtime
   from {
      configurations.runtime.collect { it.isDirectory() ? it : zipTree(it) }
   }
   exclude 'META-INF/*.DSA', 'META-INF/*.RSA', 'META-INF/*.SF'
   manifest {
      attributes('Main-Class': 'com.example.MainClass')
   }
}

Class-Path is also a valid manifest attribute, and '.' can be its value to specify the current directory to find other jars to search. This allows to use other jar files since the classpath