Hi,
How the serializable API instantiates new objects when reading from stream?
First it needs to create a new instance of a class and then fill its' fields with a serialized data. But not all serializable classes have empty constructor (as it have java beans) to make simple call of Class.newInstance(). Is there any way to create a virgin instance of any class?
Ant髇
I found the way, but it is not a solution:
Constructor serializableConstructor = sun.reflect.ReflectionFactory.getReflectionFactory().newConstructorForSerialization( Class instanceClass, Constructor superClassEmptyConstructor );
Object obj = serializableConstructor.newInstance();
This "magic" method creates an empty constructor for a serializable class from empty constructor of any superclass. The limitation is that a first non-serializable superclass must have an empty constructor.
As this magic method locates in a package sun.** I think this will not work with other JREs.
> As this magic method locates in a package sun.** I
> think this will not work with other JREs.
And you shouldn't be using it. Serialization uses it, and serialization does work on other vendor's JREs, via whatever vendor-dependent magic is required, including the above on Sun JREs, and that's all you need to know.
Hello!
You might be interested in the newly released project Objenesis, that does just that: allows the creation of objects bypassing constructors. Or, optionally, allows you to create objects in a serialization compatible way (i.e., calling the proper superclass constructor).
Check it out: http://objenesis.googlecode.com/svn/docs/index.html