[CAMEL-20436] osgi - Bean method invocations where the bean is a proxy for an Interface & the method has no arguments fail with AmbiguousMethodCallException

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Abandoned
• Affects Version/s: 3.22.1
• Component/s: osgi

Environment

Karaf 4.4.4/Java 17/Windows

• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Paul McCulloch
• Created: 19/Feb/24 15:06
• Updated: 06/May/24 11:50
• Resolved: 06/May/24 11:50

Description

Using OSGi Blueprint a <reference> element can be used to inject an OSGi service into Camel. Methods on the injected service can be called via "bean:someref?method=foo"

The service is injected as a proxy to the actual OSGi service,

When BeanInfo attempts to resolve the method it sees two methods named 'foo' : The abstract method of the interface,  and the concrete method of the proxy.

In camel 3.16 & earlier BeanInfo.findMostSpecificOverride() would determine that one method overrode the other, and would return the proxy's method.

From 3.17 onwards a changes was made to look at the method's declaring class' isSynthetic() value, and to not consider a synthetic class' method as overriding the interface. The blueprint proxy is synthetic so is affected. 

 

The changes was made for https://issues.apache.org/jira/browse/CAMEL-17844 (https://github.com/apache/camel/pull/7261/commits/5d956d2e4914a5c4fe73e5cae2f2ea7d2429f8e3)

 

This can be worked around by changing the method to take at least one argument. This triggers a different path through the code  - attempting to match the exchange body to the parameter. In this path the isSynthetic() flag isn't considered.