AbstractSet add() method in Java with Example
The add(E) method of AbstractSet Class appends the specified element to the end of this AbstractSet.
Syntax:
boolean add(E element)
Parameters: This function accepts a single parameter element as shown in the above syntax. The element specified by this parameter is appended to end of the AbstractSet.
Return Value: This method returns True after successful execution, else False.
Exception: This method throws:
- UnsupportedOperationException: if the add operation is not supported by this collection
- ClassCastException: if the class of the specified element prevents it from being added to this collection
- NullPointerException: if the specified element is null and this collection does not permit null elements
- IllegalArgumentException: if some property of the element prevents it from being added to this collection
- IllegalStateException: if the element cannot be added at this time due to insertion restrictions
Below program illustrates the working of java.util.AbstractSet.add(E element) method:
Example 1:
import java.util.*;
public class AbstractSetDemo {
public static void main(String args[])
{
AbstractSet<String> set
= new TreeSet<String>();
set.add( "Geeks" );
set.add( "for" );
set.add( "Geeks" );
set.add( "10" );
set.add( "20" );
System.out.println( "The AbstractSet is: "
+ set);
set.add( "Last" );
set.add( "Element" );
System.out.println( "The new AbstractSet is: "
+ set);
}
}
|
Output:
The AbstractSet is: [10, 20, Geeks, for]
The new AbstractSet is: [10, 20, Element, Geeks, Last, for]
Example 2: To demonstrate NullPointerException
import java.util.*;
public class AbstractSetDemo {
public static void main(String args[])
{
AbstractSet<Integer> set
= new TreeSet<Integer>();
set.add( 10 );
set.add( 20 );
set.add( 30 );
set.add( 40 );
set.add( 50 );
System.out.println( "The AbstractSet is: "
+ set);
System.out.println( "Trying to add null" );
try {
set.add( null );
}
catch (Exception e) {
System.out.println(e);
}
}
}
|
Output:
The AbstractSet is: [10, 20, 30, 40, 50]
Trying to add null
java.lang.NullPointerException
Last Updated :
24 Dec, 2018
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