Java.util.Collections.disjoint() Method in java with Examples

java.util.Collections.disjoint() method is present in java.util.Collections class. It is used to check whether two specified collections are disjoint or not. More formally, two collections are disjoint if they have no elements in common.

Syntax:
public static boolean disjoint(Collection<?> c1, Collection<?> c2)
Parameters : 
c1 - a collection
c2 - a collection
Returns :
true if the two specified collections have no elements in common.
Throws:
NullPointerException - if either collection is null.
NullPointerException - if one collection contains a null element and null is not an eligible 
element for the other collection.
ClassCastException - if one collection contains an element that is of a type which is ineligible
 for the other collection.

Note that it is permissible to pass the same collection in both parameters, in which case the method will return true if and only if the collection is empty. Output:

is mylist1 disjoint to mylist2 : true
is mylist1 disjoint to mylist3 : false
is mylist1 disjoint to mylist4 : false

How to quickly check whether two arrays in Java are disjoint or not?

Arrays class in Java doesn’t have disjoint method. We can use Collections.disjoint() to check quickly disjoincy of two arrays.

Output:

is arr1 disjoint to arr2 : true
is arr1 disjoint to arr3 : false
is arr1 disjoint to arr4 : true