Handle scoped proxy properly in MBeanExporter

Previously, if a bean has a scoped proxy and is annotated to be exposed
to the JMX domain, both the scoped proxy and the target instance were
exposed in the JMX domain, resulting in a duplicate entries. Worse, if
such bean defines an explicit name, the application wouldn't start
because of a name conflict.

This commit deals explicitely with scoped proxy and make sure to only
expose the relevant bean.

Issue: SPR-12529

spring-context/src/test/java/org/springframework/jmx/export/annotation/EnableMBeanExportConfigurationTests.java

@@ -29,6 +29,8 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.EnableMBeanExport;
 import org.springframework.context.annotation.Lazy;
 import org.springframework.context.annotation.MBeanExportConfiguration;
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
 import org.springframework.jmx.export.MBeanExporterTests;
 import org.springframework.jmx.export.TestDynamicMBean;
 import org.springframework.jmx.support.MBeanServerFactoryBean;
@@ -62,6 +64,20 @@ public class EnableMBeanExportConfigurationTests {
 		}
 	}
 
+	@Test
+	public void testOnlyTargetClassIsExposed() throws Exception {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(
+				ProxyConfiguration.class);
+		try {
+			MBeanServer server = (MBeanServer) ctx.getBean("server");
+			ObjectName oname = ObjectNameManager.getInstance("bean:name=testBean4");
+			assertNotNull(server.getObjectInstance(oname));
+			assertEquals("TEST", server.getAttribute(oname, "Name"));
+		} finally {
+			ctx.close();
+		}
+	}
+
 	@Test
 	public void testPlaceholderBased() throws Exception {
 		MockEnvironment env = new MockEnvironment();
@@ -151,6 +167,26 @@ public class EnableMBeanExportConfigurationTests {
 		}
 	}
 
+	@Configuration
+	@EnableMBeanExport(server = "server")
+	static class ProxyConfiguration {
+
+		@Bean
+		public MBeanServerFactoryBean server() throws Exception {
+			return new MBeanServerFactoryBean();
+		}
+
+		@Bean
+		@Lazy
+		@Scope(proxyMode = ScopedProxyMode.TARGET_CLASS)
+		public AnnotationTestBean testBean() {
+			AnnotationTestBean bean = new AnnotationTestBean();
+			bean.setName("TEST");
+			bean.setAge(100);
+			return bean;
+		}
+	}
+
 
 	@Configuration
 	@EnableMBeanExport(server = "${serverName}")