import java.io.*;
import org.apache.commons.codec.binary.Base64;

int i = -1;
byte[] b = new byte[4096];
ByteArrayOutputStream baos = new ByteArrayOutputStream();
while ((i = inputStream.read(b)) != -1) {
	baos.write(b, 0, i);
}

byte[] encoded = Base64.encodeBase64(baos.toByteArray());
service.getOutputStream().write(new String(encoded).getBytes());