[parker89]

Some setters work through reflection but fail Blackbird's generated accessor, either during setup or when called. Regular beans can fail deserialization or fall back to reflection on every call. These problems already exist in released versions; they aren't caused by the builder change in #364.

First in the stack: #366 → #364 → #367. This fix stands on its own.

Leave a property to MethodProperty when:

• The receiver or parameter types are inaccessible from the accessor, or can't be shown to be the same classes through its loader.
• The identity of the return type or a narrowed receiver's declaring class cannot be established safely.
• lookup.unreflect rejects an inherited setter that reflection can call.

Accessibility uses Lookup.accessClass on Java 9+ and a conservative package/loader check on Java 8. None of these checks loads a class: the receiver, parameter and return types, and a narrowed receiver's declaring class, must be defined by the accessor's own loader or be java.* types. Asking a child-first loader can otherwise define a conflicting copy, which can't be undone and breaks application code. As a result, properties with cross-loader signatures (including JDK javax.* types) may use reflection. Unsupported setters, such as double, bypass these checks.

When a check cannot establish that optimization is safe, the property stays reflective. Tests cover inaccessible types, child-first loaders, inherited setters, and checks that must not load classes, including that the application's own code still works afterwards. All Blackbird tests pass on Java 8, 11, 17 and 25.