<dependency> <groupId>org.jetbrains.kotlin</groupId> <artifactId>kotlin-stdlib-jdk8</artifactId> <version>1.6.0</version> </dependency> groovy implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0' kotlin val numbers = listOf(1, 2, 3, 4, 5) val evenNumbers = numbers.filter { it % 2 == 0 } kotlin val numbers = listOf(1, 2, 3, 4, 5) val sum = numbers.stream().mapToInt { it }.sum() kotlin val nullableValue: String? = null val value = nullableValue.toOption().getOrElse { "Default" }