Java.net.URLDecoder class in Java

1. Alphanumeric characters and certain special characters such as '*', '_', '-' and '.' remains unchanged.
2. '+' signs are converted into spaces.
3. All other characters are decoded using the encoding scheme specified. The string of the form %xy, is converted to the character whose encoding would have resulted in this three character representation. W3C recommends using "UTF-8" for encoding purposes.

u%40geeks+for+geeks

u@geeks for geeks

decode() : This is one and only method provided by this class. It as the name suggests returns an decoded string for the specified string. One method, which is now deprecated has only one parameter, the string to be decoded. It doesn't let you specify the encoding scheme used and uses the platform default encoding scheme. Another version allows the specification of the encoding to be used, and thus is widely used.

Syntax :public static String decode(String s)- @Deprecated
Parameters :
s : encoded string to be decoded

Syntax :public static String decode(String s,
            String enc)
                     throws UnsupportedEncodingException
Parameters : 
s : string to be decoded
enc : encoding to be used
Throws :
UnsupportedEncodingException : If the specified encoding is not used

// Java program to show decode() method of 
// URLDecoder class
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;

public class urlDecoder 
{
    public static void main(String[] args) 
                             throws UnsupportedEncodingException 
    {
        // encoded string
        String encodedString = "u%40geeks+for+geeks";
        System.out.println("Encoded String :");
        System.out.println(encodedString);
        
        // decode() method
        System.out.println("Decoded String :");
        System.out.println(URLDecoder.decode(encodedString, "UTF-8"));
    }
}

Encoded String :
u%40geeks+for+geeks
Decoded String :
u@geeks for geeks