Java Collections newSetFromMap() Method

The newSetFromMap() method of Java Collections class is used to return a set backed by the specified map. The resulting set displays the same ordering, concurrency, and performance characteristics as the backing map.

Syntax

Following is the declaration of newSetFromMap() method:

Parameter

Returns

The newSetFromMap() method returns the set backed by the specified map.

Exceptions

IllegalArgumentException- It throws this exception if map is not empty.

Compatibility Version

Java 1.6 and above

Example 1

Output:

 Set is: [Karan, Raj, Rahul] Map is: {Karan=true, Raj=true, Rahul=true} 

Example 2

Output:

 Set is: [1] Map is: {1=true} 

Example 3

Output:

 Users: [] Users: [Java, PHP]