MIME headers are encoded as per RFC 2047, therefore you need to decode them first.
String decoded = MimeUtility.decodeText("Georg =?ISO-8859-1?Q?SP=E4the?=");
JDK import:
import javax.mail.internet.MimeUtility;
For Android:
import com.android.email.mail.internet;
See also Javadoc of MimeUtility