The toString() method of JavaAbstractClass is used to return a string representation of the elements of the Collection.
The String representation comprises a list representation of the elements of the Collection in the order they are picked by the iterator closed in square brackets[].This method is used mainly to display collections other than String type(for instance: Object, Integer)in a String Representation.
Syntax:
Object.toString();
Parameter The method does not take any parameters.
Return This method returns a string representation of the collection.
Below examples illustrate the toString() method:
Example 1:
// Java program to demonstrate// Abstract Collection toString() method  import java.util.*;  public class collection {    public static void main(String args[])    {        // Creating an Empty AbstractCollection        AbstractCollection<String> abs            = new PriorityQueue<String>();          // Use add() method        // to add elements to the Collection        abs.add("Welcome");        abs.add("To");        abs.add("Geeks");        abs.add("For");        abs.add("Geeks");          // Using toString() method        System.out.println(abs.toString());    }} |
Output:
[For, Geeks, To, Welcome, Geeks]
Example 2:
// Java program to demonstrate// Abstract Collection toString() method  import java.util.*;  public class collection {    public static void main(String args[])    {        // Creating an Empty AbstractCollection        AbstractCollection<Integer> abs            = new PriorityQueue<Integer>();          // Use add() method        // to add elements to the Collection        abs.add(10);        abs.add(20);        abs.add(30);        abs.add(40);          // Using toString() method        System.out.println(abs.toString());    }} |
Output:
[10, 20, 30, 40]
Reference: https://docs.oracle.com/javase/9/docs/api/java/util/AbstractCollection.html#toString–
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