AbstractCollection toString() method in Java with Examples

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–