JCacheCache doesn't recognize null values in other JVMs [SPR-13553]

[spring-projects-issues]

John J Kennedy opened SPR-13553 and commented

The JCacheCache class uses an instance variable called "NULL_HOLDER" to check for a null value. The problem is that it uses == as the test. This won't work in multiple JVMs since one JVM could put a value in cache and another could retrieve it.

I believe it should use a class-based comparision like
storeValue.getClass() == NullHolder.class

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Affects: 3.2.14, 4.1.7, 4.2.1

Issue Links:

• AbstractValueAdaptingCache does not allow for flexible null value serialization [SPR-15693] #20252 AbstractValueAdaptingCache does not allow for flexible null value serialization

Referenced from: commits de93290, 6c138d3, 112781f

Backported to: 4.1.8, 3.2.15

[spring-projects-issues]

John J Kennedy commented

I can make a pull-request for this, if you want.

[spring-projects-issues]

Juergen Hoeller commented

Indeed, the NullHolder class should be designed to expect unique deserialization. The cleanest approach would be to declare a readResolve() method that always resolves to the canonical instance. I'll have a look at this for 4.2.2 and 4.1.8 still.

[spring-projects-issues]

Juergen Hoeller commented

Addressed in 4.2.2 through a larger refactoring towards the new AbstractValueAdaptingCache base class. To be backported to 4.1.8 in a minimal form, just adding readResolve() declarations.

Juergen