- Java.util Package Classes
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- Java.util - ArrayDeque
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- Java.util - EnumMap
- Java.util - EnumSet
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- Java.util - GregorianCalendar
- Java.util - HashMap
- Java.util - HashSet
- Java.util - Hashtable
- Java.util - IdentityHashMap
- Java.util - LinkedHashMap
- Java.util - LinkedHashSet
- Java.util - LinkedList
- Java.util - ListResourceBundle
- Java.util - Locale
- Java.util - Observable
- Java.util - PriorityQueue
- Java.util - Properties
- Java.util - PropertyPermission
- Java.util - PropertyResourceBundle
- Java.util - Random
- Java.util - ResourceBundle
- Java.util - ResourceBundle.Control
- Java.util - Scanner
- Java.util - ServiceLoader
- Java.util - SimpleTimeZone
- Java.util - Stack
- Java.util - StringTokenizer
- Java.util - Timer
- Java.util - TimerTask
- Java.util - TimeZone
- Java.util - TreeMap
- Java.util - TreeSet
- Java.util - UUID
- Java.util - Vector
- Java.util - WeakHashMap
- Java.util Package Extras
- Java.util - Interfaces
- Java.util - Exceptions
- Java.util - Enumerations
- Java.util Useful Resources
- Java.util - Useful Resources
- Java.util - Discussion
Java IdentityHashMap containsValue() Method
Description
The Java IdentityHashMap containsValue(Object value) method is used to test whether the specified object reference is a value in this identity hash map.
Declaration
Following is the declaration for java.util.IdentityHashMap.containsValue() method.
public boolean containsValue(Object value)
Parameters
value − This is the possible value to be checked.
Return Value
The method call returns 'true' if this map maps one or more keys to the specified object reference.
Exception
NA
Checking Value to Exist in an IdentityHashMap of Integer, Integer Pair Example
The following example shows the usage of Java IdentityHashMap containsValue() method to check if a value is present in a Map or not. We've created a Map object of Integer,Integer pairs. Then few entries are added, map is printed and using containsValue() we're checking about two values in the map.
package com.tutorialspoint; import java.util.IdentityHashMap; public class IdentityHashMapDemo { public static void main(String args[]) { // create hash map IdentityHashMap<Integer,Integer> newmap = new IdentityHashMap<>(); // populate hash map newmap.put(1, 1); newmap.put(2, 2); newmap.put(3, 3); System.out.println("Initial map elements: " + newmap); System.out.println("Map contains 2 as value: " + newmap.containsValue(2)); System.out.println("Map contains 4 as value: " + newmap.containsValue(4)); } }
Output
Let us compile and run the above program, this will produce the following result.
Initial map elements: {2=2, 3=3, 1=1} Map contains 2 as value: true Map contains 4 as value: false
Checking Value to Exist in an IdentityHashMap of Integer, String Pair Example
The following example shows the usage of Java IdentityHashMap containsValue() method to check if a value is present in a Map or not. We've created a Map object of Integer,String pairs. Then few entries are added, map is printed and using containsValue() we're checking about two values in the map.
package com.tutorialspoint; import java.util.IdentityHashMap; public class IdentityHashMapDemo { public static void main(String args[]) { // create hash map IdentityHashMap<Integer,String> newmap = new IdentityHashMap<>(); // populate hash map newmap.put(1, "tutorials"); newmap.put(2, "point"); newmap.put(3, "is best"); System.out.println("Initial map elements: " + newmap); System.out.println("Map contains tutorials as value: " + newmap.containsValue("tutorials")); System.out.println("Map contains java as value: " + newmap.containsValue("java")); } }
Output
Let us compile and run the above program, this will produce the following result.
Initial map elements: {2=point, 3=is best, 1=tutorials} Map contains tutorials as value: true Map contains java as value: false
Checking Value to Exist in an IdentityHashMap of Integer, Object Pair Example
The following example shows the usage of Java IdentityHashMap containsValue() method to check if a value is present in a Map or not. We've created a Map object of Integer,Student pairs. Then few entries are added, map is printed and using containsValue() we're checking about two values in the map.
package com.tutorialspoint; import java.util.IdentityHashMap; public class IdentityHashMapDemo { public static void main(String args[]) { // create hash map IdentityHashMap<Integer,Student> newmap = new IdentityHashMap<>(); // populate hash map newmap.put(1, new Student(1, "Julie")); newmap.put(2, new Student(2, "Robert")); newmap.put(3, new Student(3, "Adam")); System.out.println("Initial map elements: " + newmap); System.out.println("Map contains Robert as value: " + newmap.containsValue(new Student(2, "Robert"))); System.out.println("Map contains Jene as value: " + newmap.containsValue(new Student(4, "Jene"))); } } class Student { int rollNo; String name; Student(int rollNo, String name){ this.rollNo = rollNo; this.name = name; } @Override public String toString() { return "[ " + this.rollNo + ", " + this.name + " ]"; } @Override public boolean equals(Object obj) { if(obj == null) return false; Student s = (Student)obj; return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name); } }
Output
Let us compile and run the above program, this will produce the following result.
Initial map elements: {1=[ 1, Julie ], 3=[ 3, Adam ], 2=[ 2, Robert ]} Map contains Robert as value: false Map contains Jene as value: false
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