AbstractMap.SimpleEntry<K, V> is used to maintain a key and a value entry. The value can be changed using the setValue method. This class facilitates the process of building custom map implementations. getKey() method of AbstractMap.SimpleEntry<K, V> returns the key corresponding to this entry.
Syntax:
public K getKey()
Parameters: This method accepts nothing.
Return value: This method returns the key corresponding to this entry.
Below programs illustrate getKey() method:
Program 1:
Java
// Java program to demonstrate// AbstractMap.SimpleEntry.getKey() methodimport java.util.*;import java.util.AbstractMap.SimpleEntry;public class GFG { @SuppressWarnings({ "unchecked", "rawtypes" }) public static void main(String[] args) { // create a ArrayList of Map ArrayList<AbstractMap .SimpleEntry<Integer, Integer> > arrayList = new ArrayList<AbstractMap .SimpleEntry<Integer, Integer> >(); // add values arrayList.add(new AbstractMap.SimpleEntry(0, 123)); arrayList.add(new AbstractMap.SimpleEntry(1, 130)); arrayList.add(new AbstractMap.SimpleEntry(2, 994)); // print keys for (int i = 0; i < arrayList.size(); i++) { // get map from list AbstractMap.SimpleEntry<Integer, Integer> map = arrayList.get(i); // get key from map.getKey(); int key = map.getKey(); System.out.println("Key " + key); } }} |
Output:
Key 0 Key 1 Key 2
Program 2:
Java
// Java program to demonstrate// AbstractMap.SimpleEntry.getkey() methodimport java.util.*;public class GFG { @SuppressWarnings({ "unchecked", "rawtypes" }) public static void main(String[] args) { // create a ArrayList of Map ArrayList<AbstractMap .SimpleEntry<String, String> > arrayList = new ArrayList<AbstractMap .SimpleEntry<String, String> >(); // add values arrayList.add(new AbstractMap .SimpleEntry(" 001AB ", " Emp 1")); arrayList.add(new AbstractMap .SimpleEntry(" 011AC ", " Emp 2")); arrayList.add(new AbstractMap .SimpleEntry(" 111AD ", " Emp 3")); arrayList.add(new AbstractMap .SimpleEntry(" 101BE ", " Emp 4")); arrayList.add(new AbstractMap .SimpleEntry(" 110CE ", " Emp 5")); // print keys for (int i = 0; i < arrayList.size(); i++) { // get map from list AbstractMap.SimpleEntry<String, String> map = arrayList.get(i); // get key from map.getKey() String key = map.getKey(); System.out.println("Key " + key); } }} |
Output:
Key 001AB Key 011AC Key 111AD Key 101BE Key 110CE
References: https://docs.oracle.com/javase/10/docs/api/java/util/AbstractMap.SimpleEntry.html#getKey()
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