No subclass matches this class; for this Aggregate mapping with inheritance.

No subclass matches this class [class com.baselogic.test.CustomerFixture$2$1] for this Aggregate mapping with inheritance

I have been writing a chapter for my new book “Java EE6 Cookbook for Securing, Tuning and Extending Enterprise applications” today, and I ran across an interesting error based on a JPA testing pattern.

I have used 2 patterns for seeding data to test some @CollectionTable functionality.
First, I used DBUnit to seed my data, and that seems to work just fine for adding @CollectionTable relationships.

The second seemed fairly straight forward. I wanted to create a Fixture utility to create an entity to insert

Customer customer = CustomerFixture.createSingleCustomer();

My CustomerFixture.createSingleCustomer() is fairly simple

    public static Customer createSingleCustomer() {
        Customer customer = new Customer();
        customer.setUsername("testusername");
        customer.setFirstName("Mick");
        customer.setLastName("Knutson");
        customer.setDescription("Customer with an Android Device.");
        customer.setHobbies(
                new HashSet<String>() {{
                    add("BASE-Jumping");
                    add("Skydiving");
                    add("Speed-Flying");
                }}
        );
        customer.setPhones(createPhones());
        customer.setAddresses(createAddresses());
        return customer;
    }

I was adding Address’s that looked like this

    public static Map<String, Address> createAddresses() {
        final int pk = getRandomInt(1, 999);
        return new HashMap<String, Address>() {{
            put(String.format("%03d", pk),
                    new Address(){{
                        setType(AddressType.RESIDENTIAL);
                        setStreet("123 Main Street");
                        setCity("San Francisco");
                        setState("CA");
                        setPostCode("91335");
                        setProvince("");
                    }}
            );
        }};
    }

Notice that I created the Address with a default constructor…?

When running this, I get a very interesting exception:

javax.persistence.EntityExistsException:
Exception Description: No subclass matches this class [class com.baselogic.test.CustomerFixture$2$1] for this Aggregate mapping with inheritance.
Mapping: org.eclipse.persistence.mappings.AggregateCollectionMapping[addresses]
Descriptor: RelationalDescriptor(com.baselogic.chapter02.Customer --> [DatabaseTable(CUSTOMER)])

What I finally tracked this down to was from skimming the XXX codes on http://wiki.eclipse.org/EclipseLink_Exception_Error_Reference_%28ELUG%29

ECLIPSELINK-00068: The value of an aggregate in object [{0}] is null. Null values not allowed for Aggregate mappings unless “Allow Null” is specified.
Cause: The value of the aggregate in the source object object is null. Null values are not allowed for aggregate mappings unless allow null is specified in the aggregate mapping.
Action: Call the mapping method allowNull. Provide parameters only if you are making a distinction between foo() and foo(integer).

Specifically the ‘Action’.
So I started looking at my Fixture, and constructed my Address with a specific Constructor:

    public static Map<String, Address> createAddresses(){
        final int pk = getRandomInt(1, 999);
        return new HashMap<String, Address>(){{
            put(String.format("%03d", pk),
                new Address(
                        AddressType.RESIDENTIAL,
                        "123 Main Street",
                        "San Francisco",
                        "CA",
                        "94114"
                )
            );
        }};
    }

This solved the issue, and the seeding of the Customer succeeded.