CDI object not proxyable with injected constructor

Question

When trying to inject arguments into the constructor of a CDI bean (ApplicationScoped), I'm encountering the following issue:

Caused by: org.jboss.weld.exceptions.UnproxyableResolutionException: WELD-001435: Normal scoped bean class xx.Config is not proxyable because it has no no-args constructor - Managed Bean [class xx.Config] with qualifiers [@Default @Named @Any].
    at org.jboss.weld.bean.proxy.DefaultProxyInstantiator.validateNoargConstructor(DefaultProxyInstantiator.java:50)
    at org.jboss.weld.util.Proxies.getUnproxyableClassException(Proxies.java:217)
    at org.jboss.weld.util.Proxies.getUnproxyableTypeException(Proxies.java:178)

However, I do have an injectable constructor on the class:

@Inject
public Config(ConfigLocator configLocator) {
    defaultConfigPath = configLocator.getPath();
    doStuff();
}

With a default constructor, variable injection and a postconstruct method, this all works fine, but I'd prefer the constructor injection in this case.

Any thoughts what is going wrong here?

Answer 1

We resolved similar problem splitting class into interface and implementation. In your case something like this:

public interface Config
{
  // API here
}

@ApplicationScoped @Priority(0)
public class ConfigImpl implements Config
{
  @Inject
  public ConfigImpl(ConfigLocator configLocator) { ... }

  // API implementation here
}

Answer 2

This example might help you :

@ApplicationScoped
public class Config {

    private String defaultConfigPath;  

    @Inject
    public Config(ConfigLocator configLocator) {
       this.defaultConfigPath = configLocator.getPath();
       doStuff();
    }

    // create a no-args constructor which is required for any scoped bean.
    public Config() {
    }

}

You need to have a public non-args constructor in the @ApplicationScoped bean.

Note : The bean for this class will created only once and is maintained for the entire life of an application. This bean will shared among all the managed beans. @ApplicationScoped beans are singleton in nature.

The mentioned issue:

Caused by: org.jboss.weld.exceptions.UnproxyableResolutionException: WELD-001435: Normal scoped bean class xx.Config is not proxyable because it has no no-args constructor - Managed Bean [class xx.Config] with qualifiers [@Default @Named @Any].

The possible reason for this is that a non-dependent scoped bean is required to provide a public no-args constructor for CDI, so that it can pick up the desired proxy bean at runtime.