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https://issues.apache.org/jira/browse/OWB-1234?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mark Struberg reassigned OWB-1234:
----------------------------------
Assignee: Mark Struberg
> generic classes are not correctly proxied when bridge methods are involved
> --------------------------------------------------------------------------
>
> Key: OWB-1234
> URL: https://issues.apache.org/jira/browse/OWB-1234
> Project: OpenWebBeans
> Issue Type: Bug
> Components: Interceptor and Decorators
> Affects Versions: 2.0.4
> Reporter: Alexander Zapletal
> Assignee: Mark Struberg
> Priority: Major
>
> Proxies generated by _NormalScopeProxyFactory_ do not contain (overriding)
> proxy methods for bridge methods, because bridge methods are generally
> ignored by the proxy generation, see
> _AbstractProxyFactory.unproxyableMethod()_ and
> _ClassUtil.addNonPrivateMethods()_ .
> (See also OWB-923)
> But this can lead to wrong proxies:
> {code:java}
> interface Contract {
> void doIt(Integer param);
> }
> {code}
> {code:java}
> public class BaseBean<T extends Number> {
> public void doIt(T param) {
> }
> }
> {code}
> {code:java}
> @ApplicationScoped
> public class MyBean extends BaseBean<Integer> implements Contract {
> }
> {code}
> When compiling this code the compiler performs type erasure and needs to
> generate a bridge method. The generated byte code corresponds (roughly) to
> the following code:
> {code:java}
> public class BaseBean {
> public void doIt(Number param) {
> }
> }
> {code}
> {code:java}
> public class MyBean {
> // bridge method!
> public void doIt(Integer param) {
> super.doIt(param);
> }
> }
> {code}
> _NormalScopeProxyFactory_ generates a proxy class that (roughly) corresponds
> to the following code:
> {code:java}
> public class MyBean$$OwbNormalScopeProxy extends MyBean {
>
> public void doIt(Number var1) {
> ((MyBean)this.owbContextualInstanceProvider.get()).doIt(var1);
> }
> }
> {code}
> But when we now call, for instance, _doIt(4711)_ on an injected instance of
> _Contract_ , we actually call _MyBean.doIt(Integer)_ and thereby we bypass
> the proxy!
> {code:java}
> @Inject Contract handler;
> handler.doIt(4711)
> {code}
> Reason: When _NormalScopeProxyFactory_ generated the proxy for _MyBean,_ it
> found the following two methods (amongst others):
> {code:java}
> void doIt(Number var1) // inherited from BaseBean
> void doIt(Integer var1) // bridge method
> {code}
> Since _NormalScopeProxyFactory_ ignores bridge methods, it only generated a
> proxy method for _doIt(Number)_ . This method *overloads*
> _MyBean.doIt(Integer)_ , it does not *override* it. So, _handler.doIt(4711)_
> actually calls _MyBean.doIt(Integer)_ .
>
> *IMPORTANT NOTE:* There is a quite simple workaround for this problem: Just
> implement the bridge method yourself. I.e. in the example above use the
> following implementation
> {code:java}
> @ApplicationScoped
> public class MyBean extends BaseBean<Integer> implements Contract {
> @Override
> public void doIt(Integer param) {
> super.doIt(param);
> }
> }
> {code}
> Now, the method _doIt(Integer)_ is not a bridge method anymore and
> _NormalScopeProxyFactory_ will generate a proxy method for it.
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