I have just tried a sample code form net it shows a warning as follows
SimpleConvertImage.java:7: warning:com.sun.org.apache.xerces.internal.impl.dv.u
You can also use: java.util.Base64 Added to Java 1.8
String encryptedValue = new String(Base64.getEncoder().encode(bytesToEncode));
byte[] decodedValue = Base64.getDecoder().decode(encryptedDataString);
Don't use internal com.sun.* packages. If you are on v6 or greater you can use DatatypeConverter. Your code would look like:
String base64String = DatatypeConverter.printBase64Binary(baos.toByteArray());
byte[] bytearray = DatatypeConverter.parseBase64Binary(base64String);