build1.gradle

android {

	productFlavors {
		
	}

	productFlavors['flavor1'] << {
		packageName "com.example.flavor1"
	}
 
	productFlavors['flavor2'] << {
		packageName "com.example.flavor2"
	}
}

/*

A problem occurred evaluating root project 'MyProject'.
> GroupableProductFlavorDsl with name 'flavor1' not found.

*/

build2.gradle

android {

	productFlavors {
		
	}

	productFlavors['flavor1'] = {
		packageName "com.example.flavor1"
	}
 
	productFlavors['flavor2'] = {
		packageName "com.example.flavor2"
	}
}

/*

no error, but does not work

*/

build3.gradle

android {

	productFlavors {
		
	}

	productFlavors['flavor1'] = [packageName: "com.example.flavor1"]
 
	productFlavors['flavor2'] = [packageName: "com.example.flavor2"]
}

/*

no error, but does not work

*/

build4.gradle

android {

	productFlavors {
		['flavor1'] << {
			packageName: "com.example.flavor1"
		}
		['flavor2'] << {
			packageName: "com.example.flavor2"	
		}
	}

}

/*

no error, but does not work

*/

build5.gradle

android {

	productFlavors {
		['flavor1'] << {
			packageName: "com.example.flavor1"
		}
		['flavor2'] << {
			packageName: "com.example.flavor2"	
		}
	}

}

/*

no error, but does not work

*/