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.
hashCode() method of AbstractMap.SimpleEntry<K, V> return the hash code value for this map entry.
The hash code for the map entry e can be calculated by:
(e.getKey()==null ? 0 : e.getKey().hashCode()) ^ (e.getValue()==null ? 0 : e.getValue().hashCode())
Syntax:
public int hashCode()
Parameters: This method accepts nothing.
Return value: This method return the hash code value for this map entry.
Below programs illustrate hashCode() method:
Program 1:
// Java program to demonstrate // AbstractMap.SimpleEntry.hashCode() method import 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 value from map using hashCode()
int value = map.hashCode();
System.out.println( "HashCode = " + value);
}
}
} |
HashCode = 123 HashCode = 131 HashCode = 992
Program 2:
// Java program to demonstrate // AbstractMap.SimpleEntry.hashCode() method import 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 hashcode value from map using hashCode()
int value = map.hashCode();
System.out.println( "hashCode = " + value);
}
}
} |
hashCode = -873386249 hashCode = -874293612 hashCode = -910934441 hashCode = -910552137 hashCode = -910906733
References: https://docs.oracle.com/javase/10/docs/api/java/util/AbstractMap.SimpleEntry.html#hashCode()