範例

public static class Object1 implements Externalizable{

private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
s.defaultReadObject();
}
}

解決方案
實作 Externalizable 的類別一律應該有不含引數的建構子


public static class Object1 implements Externalizable{

private Object1 (){

}

private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
s.defaultReadObject();
}
}