Sizing Hash Maps: find out the number of key-value pairs within the HashMap : HashMap « Collections « Java Tutorial

1. Java Tutorial
2. Collections
3. HashMap

public int size()
public boolean isEmpty()

import java.util.HashMap;
import java.util.Map;

public class MainClass {
  public static void main(String[] a) {

    Map map = new HashMap();
    map.put("key1", "value1");
    map.put("key2", "value2");
    map.put("key3", "value3");

    System.out.println(map.size());
  }
}

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