in src/main/java/org/apache/openejb/tools/release/util/Base64.java [176:184]
private static boolean isBase64(final byte octect) {
if (octect == PAD) {
return true;
} else if (octect < 0 || base64Alphabet[octect] == -1) {
return false;
} else {
return true;
}
}