- Java.util Package Classes
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- Java.util - HashMap
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- 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
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- Java.util - ResourceBundle.Control
- Java.util - Scanner
- Java.util - ServiceLoader
- Java.util - SimpleTimeZone
- Java.util - Stack
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- 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
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- Java.util - Discussion
Java WeakHashMap containsValue() Method
Description
The Java WeakHashMap containsValue(Object value) method is used to return true if this map, maps one or more keys to the specified value.
Declaration
Following is the declaration for java.util.WeakHashMap.containsValue() method.
public boolean containsValue(Object value)
Parameters
value − The value is the input whose presence in this map is to be tested.
Return Value
The method call returns true if this map maps one or more keys to the specified value.
Exception
NA
Checking Presence of a Value in a WeakHashMap of Integer, Integer Pairs Example
The following example shows the usage of Java WeakHashMap 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.WeakHashMap; public class WeakHashMapDemo { public static void main(String args[]) { // create hash map WeakHashMap<Integer,Integer> newmap = new WeakHashMap<>(); // 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: {3=3, 2=2, 1=1} Map contains 2 as value: true Map contains 4 as value: false
Checking Presence of a Value in a WeakHashMap of Integer, String Pairs Example
The following example shows the usage of Java WeakHashMap 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.WeakHashMap; public class WeakHashMapDemo { public static void main(String args[]) { // create hash map WeakHashMap<Integer,String> newmap = new WeakHashMap<>(); // 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: {3=is best, 2=point, 1=tutorials} Map contains tutorials as value: true Map contains java as value: false
Checking Presence of a Value in a WeakHashMap of Integer, Object Pairs Example
The following example shows the usage of Java WeakHashMap containsValue() method to check if a value is present in a Map or not. We've created a Map object of Integer,Student pair. 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.WeakHashMap; public class WeakHashMapDemo { public static void main(String args[]) { // create hash map WeakHashMap<Integer,Student> newmap = new WeakHashMap<>(); // 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: {3=[ 3, Adam ], 2=[ 2, Robert ], 1=[ 1, Julie ]} Map contains Robert as value: true Map contains Jene as value: false
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