Java Collections Java
Following example shows how to find intersection of multiple collections.
public class CollectionIntersection {
public static <T, C extends Collection<T>> C findIntersection(C newCollection,
Collection<T>... collections) {
boolean first = true;
for (Collection<T> collection : collections) {
if (first) {
newCollection.addAll(collection);
first = false;
} else {
newCollection.retainAll(collection);
}
}
return newCollection;
}
public static void main(String[] args) {
List<Integer> l1 = List.of(1, 3, 5, 7, 9, 11, 13);
List<Integer> l2 = List.of(1, 2, 3, 5, 8, 13);
List<Integer> l3 = List.of(2, 3, 5, 7, 11, 13);
Set<Integer> intersection = findIntersection(new HashSet<>(), l1, l2, l3);
System.out.println(intersection);
}
} [3, 5, 13]
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