The implementation is the easy phase of the serializable class. At first this interface remains as an empty interface and it declares no methods or behavior at all. It has additing feature that is added to the implements serializable class to follow the class declarations. It is not required to make every object as serializable as there will also be some classes that might not be having any serialization required. 

For example, an instance of a file that actually REPRESENTS a file GETS created by using File file = new File("c:\career\ride");

so to make this WORK there is no SURITY that is it require a serialized code to be written. The file class is having a different lifecyle than the serialized data and MODIFICATION in it might remove the entire information. There are also platform dependencies that involves native code not used for serialization.

The implementation is the easy phase of the serializable class. At first this interface remains as an empty interface and it declares no methods or behavior at all. It has additing feature that is added to the implements serializable class to follow the class declarations. It is not required to make every object as serializable as there will also be some classes that might not be having any serialization required. 

For example, an instance of a file that actually represents a file gets created by using File file = new File("c:\career\ride");

so to make this work there is no surity that is it require a serialized code to be written. The file class is having a different lifecyle than the serialized data and modification in it might remove the entire information. There are also platform dependencies that involves native code not used for serialization.