反序列化java.awt.Color-> java.io.InvalidClassException

Question

i want to serialize and deserialize an Object, which contains a color array. (color[][])

The color array represents a small icon.

After some Builds i get an error when i try to deserialize the object:

java.io.InvalidClassException: java.awt.Color; local class incompatible: stream classdesc serialVersionUID = 118526816875918197, local class serialVersionUID = 118526816881161077

What can i do to fix that? The Object itself has the default UID (serialVersionUID = 1L;)...

Thank you :)

Answer 1

Take a look on the error message again:

java.io.InvalidClassException: java.awt.Color; 
local class incompatible: 
stream classdesc serialVersionUID = 118526816875918197, 
local class serialVersionUID = 118526816881161077

It seems that you serialized the class using one version of Color and try to deserialize it with other.

Here is the serialVersionUID in my environment.

 private static final long serialVersionUID = 118526816881161077L;

It matches your second serialVersionUID . However the first is different: 118526816875918197 . This fact is a little bit strange because I compared this version ID with java 6 and java 7 JDK and they are equal. I cannot compare it with older JDK as well as with JDK from other vendors (not from Oracle). So I can assume that you created your file with either older version of JDK or with JDK from other vendor (eg open JDK, IBM etc.) or in other platform.

If this is the case I suggest you to customize serialization of your class by implementing your own writeObject() and readObject() methods. You do not have to re-implement serialization of all your classes. It is enough to wrap Color with your custom wrapper customize serialization for it.

BTW forward/backward compatibility of serialized object is a well known weakness of whole serialization mechanism of java. You can use alternatives, eg serialization to JSON, XML or other binary format.

For JSON you can use Jackson or Gson, for XML JAXB or Xstream, for binary format protobuff.