What is the proxyTargetClass attribute in @EnableRetry?

The proxyTargetClass attribute of @EnableRetry controls whether Spring Retry uses subclass-based CGLIB proxies or interface-based JDK dynamic proxies to intercept methods annotated with @Retryable.

Default behavior:

@EnableRetry // proxyTargetClass = false by default
public class AppConfig { }

When proxyTargetClass = false (default), Spring uses JDK dynamic proxies. This requires the bean to implement at least one interface. The @Retryable method must be declared on the interface for the proxy to intercept it.

When proxyTargetClass = true, Spring uses CGLIB to create a subclass proxy of the concrete class, so no interface is needed:

@EnableRetry(proxyTargetClass = true)
public class AppConfig { }

When to use proxyTargetClass = true:

• Your service classes do not implement interfaces
• You want retry on methods that are not declared on any interface
• You encounter proxy-related class cast exceptions at runtime

In Spring Boot applications that already use CGLIB for @Configuration classes, setting proxyTargetClass = true is consistent and avoids mixed proxy types. The CGLIB approach has a slight startup cost for proxy generation but no runtime overhead difference.