The floor() method of java.util.TreeSet<E> class is used to return the greatest element in this set less than or equal to the given element, or null if there is no such element.
public E floor(E e)
Parameters: This method takes the value e as a parameter which is to be matched.
Return Value: This method returns the greatest element less than or equal to e, or null if there is no such element
Exception: This method throws the NullPointerException if the specified element is null and this set uses natural ordering, or its comparator does not permit null elements
Below are the examples to illustrate the floor() method
TreeSet: [10, 20, 30, 40] Floor value for 25: 20
Example 2: for NullPointerException
TreeSet: [10, 20, 30, 40] Trying to get the floor value for null Exception thrown : java.lang.NullPointerException
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