Simplistic example of the Codename One Externalizable interface usage

ExternalizableSample.java

public void externalize(DataOutputStream out) throws IOException {
    out.writeUTF(name);
    if(value != null) {
        out.writeBoolean(true);
        out.writeUTF(value);
    } else {
        out.writeBoolean(false);
    }
    if(domain != null) {
        out.writeBoolean(true);
        out.writeUTF(domain);
    } else {
        out.writeBoolean(false);
    }
    out.writeLong(expires);
}

public void internalize(int version, DataInputStream in) throws IOException {
    name = in.readUTF();
    if(in.readBoolean()) {
        value = in.readUTF();
    }
    if(in.readBoolean()) {
        domain = in.readUTF();
    }
    expires = in.readLong();
}

Sample code for Externalizable.

From the Codename One project