Properties list(PrintWriter) method in Java with Examples

The list(PrintWriter) method of Properties class is used to print this Properties list out to the specified output stream, passed as the parameter. This method can be used for debugging purpose as it can help to see the Properties elements on the stream.0

Syntax:

public void list(PrintWriter out)

Parameters: This method accepts a parameters PrintWriter out which is the output stream on which the Properties elements are to be printed.

Returns: This method just prints the elements and do not return anything.

Exception: This method throws ClassCastException if any key in this property list is not a string.

Below programs show the implementation of int list(PrintWriter) method.

Program 1:

// Java code to show the implementation of
// list(PrintWriter) method

import java.util.*;
import java.io.*;

public class GfG {

    // Main method
    public static void main(String[] args)
    {

        // Create a properties and add some values
        Properties properties = new Properties();
        properties.put("Pen", "10");
        properties.put("Book", "500");
        properties.put("Clothes", "400");
        properties.put("Mobile", "5000");

        // Print Properties details
        System.out.println("Properties: "
                           + properties.toString());

        PrintWriter writer = new PrintWriter(System.out);

        // print the list with a PrintWriter object
        properties.list(writer);

        // flush the stream and display
        System.out.println("listing out the Properties: ");
        writer.flush();
    }
}

Output:

Properties: {Book=500, Mobile=5000, Pen=10, Clothes=400}
listing out the Properties: 
-- listing properties --
Book=500
Pen=10
Mobile=5000
Clothes=400

Program 2:

// Java program to demonstrate
// list(PrintWriter) method.

import java.util.*;
import java.io.*;

public class GFG {

    // Main method
    public static void main(String[] args)
    {

        // Create a properties and add some values
        Properties properties = new Properties();

        // Inserting elements into the properties
        properties.put("Geeks", "10");
        properties.put("4", "15");
        properties.put("Geeks", "20");
        properties.put("Welcomes", "25");
        properties.put("You", "30");

        // Print Properties details
        System.out.println("Properties: "
                           + properties.toString());

        PrintWriter writer = new PrintWriter(System.out);

        // print the list with a PrintWriter object
        properties.list(writer);

        // flush the stream and display
        System.out.println("listing out the Properties: ");
        writer.flush();
    }
}

Output:

Properties: {You=30, Welcomes=25, 4=15, Geeks=20}
listing out the Properties: 
-- listing properties --
You=30
4=15
Welcomes=25
Geeks=20

References: https://docs.oracle.com/javase/9/docs/api/java/util/Properties.html#list-java.io.PrintWriter-