MutableList<String> list = Lists.mutable.empty(); list.add("apple"); list.add("banana"); list.add("orange"); ImmutableList<String> filteredList = list.select(element -> element.length() > 5); ImmutableList<Integer> mappedList = list.collect(String::length); MutableList<String> list1 = Lists.mutable.with("apple", "banana"); MutableList<String> list2 = Lists.mutable.with("orange", "grape"); MutableList<String> combinedList = list1.addAll(list2); MutableMap<Integer, String> map = Maps.mutable.empty(); map.put(1, "apple"); map.put(2, "banana"); map.put(3, "orange"); import org.eclipse.collections.api.list.MutableList; import org.eclipse.collections.impl.factory.Lists; import org.eclipse.collections.impl.factory.Sets; import org.eclipse.collections.impl.factory.Maps;