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Check whether a NavigableMap empty or not in Java
The isEmpty() method is used in Java to check whether a NavigableMap is empty or not.
First, create a NavigableMap and add elements to it −
NavigableMap<Integer, String> n = new TreeMap<Integer, String>(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); n.put(4, "Jackie"); n.put(15, "Kurt"); n.put(19, "Tiger"); n.put(24, "Jacob");
Now, check whether the Map is empty or not −
System.out.println("Map is empty? " + n.isEmpty());
The following is an example to implement isEmpty() method and check whether the Map is empty −
Example
import java.util.*; public class Demo { public static void main(String[] args) { NavigableMap<Integer, String> n = new TreeMap<Integer, String>(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); n.put(4, "Jackie"); n.put(15, "Kurt"); n.put(19, "Tiger"); n.put(24, "Jacob"); System.out.println("NavigableMap elements = "+n); System.out.println("Size = "+n.size()); System.out.println("Map is empty? " + n.isEmpty()); // remove all elements n.clear(); System.out.println("
Updated NavigableMap elements = "+n); System.out.println("Size = "+n.size()); System.out.println("Map is empty? " + n.isEmpty()); } }
Output
NavigableMap elements = {1=Tim, 4=Jackie, 5=Tom, 9=John, 14=Jamie, 15=Kurt, 19=Tiger, 24=Jacob} Size = 8 Map is empty? false Updated NavigableMap elements = {} Size = 0 Map is empty? True
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