Base64 Encoding: Illegal base64 character 3c

I got this same error and problem was that the string was starting with data:image/png;base64, ...

The solution was:

byte[] imgBytes = Base64.getMimeDecoder().decode(imgBase64.split(",")[1]);

Just use this method

getMimeDecoder()

String data = "......";
byte[] dataBytes =  Base64.getMimeDecoder().decode(data);