我想序列化一个Map<String，CustomClass>对象，它包含一个静态嵌套的CustomClass对象作为它的值。

public class A{
    static Map<String, CustomClass> map = new HashMap<>();
    public static void main(String[] args) {
        map.put("ABC", new CustomClass(1, 2L, "Hello"));
        writeToFile();
    }
    
    private static void writeToFile() throws IOException, ClassNotFoundException {
        ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("file.ser"));
        out.writeObject(map);
    }
    private static class CustomClass implements Serializable {
        int x;
        long y;
        String z;
        private static final long serialVersionUID = 87923834787L;
        private CustomClass (int x, long y, String z) {
         .....
        }
    }
}
public class B {
    static Map<String, CustomClass> map = new HashMap<>();
    
    public static void main( String[] args) {
        readFromFile();
    }
    private static void readFromFile() throws IOException, ClassNotFoundException {
        ObjectInputStream out = new ObjectInputStream(new FileInputStream("file.ser"));
        map = out.readObject(); // ClassNotFoundException occured
    }
    private static class CustomClass implements Serializable {
        int x;
        long y;
        String z;
        private static final long serialVersionUID = 87923834787L;
        private CustomClass (int x, long y, String z) {
         .....
        }
        
        //some utility methods
        ....
    }
}

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当我试图读取序列化的Map对象时，它抛出ClassNotFoundException。这是因为在不同类下定义的相同嵌套类将具有不同的名称或版本吗？
这个问题的可能解决办法是什么？