Java ConcurrentHashMap forEach() Method

by Online Tutorials Library July 22, 2022

Java ConcurrentHashMap forEach() Method

The forEach() method of ConcurrentHashMap class performs the given action for each key, value pair.

Syntax

  public void forEach(long parallelismThreshold, BiConsumer<? super K,? super V> action)    public <U> void forEach(long parallelismThreshold, BiFunction<? super K,? super V,? extends U> transformer, Consumer<? super U> action)  

Parameter

parallelismThreshold – the (estimated) number of elements needed for this operation to be executed in parallel

action – the action

transformer – a function which return transformation.

Returns

true if the value was replaced

Throws

NullPointerException.

Example 1

  import java.util.concurrent.*;     import java.util.*;       public class  ConcurrentHashMapforeachExample1 {           public static void main(String[] args)       {             // crete a HashMap and add some values           HashMap mapcon               = new HashMap<>();           mapcon.put(“k1”, 100);           mapcon.put(“k2”, 200);           mapcon.put(“k3”, 300);           mapcon.put(“k4”, 400);           System.out.println(“HashMap values :n ” + mapcon.toString());            //replace the value of key k1 to 1000          mapcon.replace(“k1” , 1000);          System.out.println(“New HashMap after remove :n “+ mapcon.toString()); //print statement          mapcon.forEach( (k, v) -> System.out.printf(”    k: %s, v: %s%n”, k, v)); //foreach function      }   }   ,>

Test it Now

Output:

New HashMap after remove :   {k1=1000, k2=200, k3=300, k4=400}      k: k1, v: 1000      k: k2, v: 200      k: k3, v: 300      k: k4, v: 400

Example 2

  import java.util.*;  import java.util.concurrent.ConcurrentHashMap;    public class ConcurrentHashMapforeachExample2  {     public static void main(String args[]) {               ConcurrentHashMap  mymap = new ConcurrentHashMap();          ConcurrentHashMap  mymap2 = new ConcurrentHashMap();                mymap2.put(1, 101);        mymap2.put(2, 102);        mymap2.put(3, 103);        System.out.println(” mymap2 :” +mymap2.toString());        mymap.put(“AA”, “Java”);        mymap.put(“BB”, “angular”);        mymap.put(“CC”, “JavaScript”);        System.out.println(” mymap :” +mymap.toString());        System.out.println(“comparing mymap and mymap2 :” +mymap.equals(mymap2));        mymap.forEach( (k, v) -> System.out.printf(”    k: %s, v: %s%n”, k, v));     }      }  

Test it Now

Output:

mymap2 :{1=101, 2=102, 3=103}   mymap :{AA=Java, BB=angular, CC=JavaScript}  comparing mymap and mymap2 :false      k: AA, v: Java      k: BB, v: angular      k: CC, v: JavaScript

Next TopicJava ConcurrentHashMap

Java ConcurrentHashMap forEach() Method

Java ConcurrentHashMap forEach() Method

Syntax

Parameter

Returns

Throws

Example 1

Example 2

Java Array getShort() Method

Java ConcurrentHashMap remove() Method

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