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Editorial Team
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Asked: 2026-05-16T06:19:08+00:00

I want to reinject singleton-scoped dependencies into prototype Spring beans, after they have been

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I want to reinject singleton-scoped dependencies into prototype Spring beans, after they have been deserialized.

Say I’ve got a Process bean, which depends on a Repository bean. The Repository bean is a scoped as a singleton, but the Process bean is prototype-scoped. Periodically I serialize the Process, and then later deserialize it. 

class Process {
   private Repository repository;
   // getters, setters, etc.
}

I don’t want to serialize and deserialize the Repository. Nor do I want to put “transient” on the member variable that holds a reference to it in Process, nor a reference to some kind of proxy, or anything other than a plain old member variable declared as a Repository.

What I think I want is for the Process to have its dependency filled with a serializable proxy that points (with a transient reference) to the Repository, and, upon deserialization, can find the Repository again. How could I customize Spring to do that?

I figure I could use a proxy to hold the dependency references, much like . I wish I could use that exact technique. But the proxy I’ve seen Spring generate isn’t serializable, and the docs say that if I use it with a singleton bean, I’ll get an exception.

I could use a custom scope, perhaps, on the singleton beans, that would always supply a proxy when asked for a custom-scoped bean. Is that a good idea? Other ideas?

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1 Answer

  1. Editorial Team

    How about added using aspects to add an injection step when you deserialize the object?

    You would need AspectJ or similar for this. It would work very similarly to the @Configurable function in Spring.

    e.g. add some advice around the a “private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException” method

    This article may also help: http://java.sun.com/developer/technicalArticles/Programming/serialization/

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