URLDecoder.decode(String s)
Decodes a x-www-form-urlencoded string. The platform's default encoding is used to determine what characters are represented by any consecutive sequences of the form "%xy".
Note: It is deprecated.
URLDecoder.decode(String s, String enc)
Decodes a application/x-www-form-urlencoded string using a specific encoding scheme. The supplied encoding is used to determine what characters are represented by any consecutive sequences of the form "%xy".
Entire info you can find here.