<dependency> <groupId>org.eclipse.collections</groupId> <artifactId>eclipse-collections-api</artifactId> <version>XXXX</version> </dependency> import org.eclipse.collections.api.list.MutableList; import org.eclipse.collections.impl.list.mutable.FastList; public class Example { public static void main(String[] args) { MutableList<Integer> numbers = new FastList<>(); numbers.add(1); numbers.add(2); numbers.add(3); numbers.forEach(System.out::println); } }