src/main/java/org/jinstagram/http/URLUtils.java
public static String formURLEncode(String string) {
        Preconditions.checkNotNull(string, "Cannot encode null string");

        try {
            return URLEncoder.encode(string, UTF_8);
        } catch (UnsupportedEncodingException uee) {
            throw new IllegalStateException(ERROR_MSG, uee);
        }
    }
public static String formURLEncode(String string) {
        Preconditions.checkNotNull(string, "Cannot encode null string");

        try {
            return URLEncoder.encode(string, UTF_8);
        } catch (UnsupportedEncodingException uee) {
            throw new IllegalStateException(ERROR_MSG, uee);
        }
    }
Translates a string into application/x-www-form-urlencoded format

@param plain
@return form-urlencoded string