Review fixes for restlet-2.0:testing (#17016)

Co-authored-by: otelbot <197425009+otelbot@users.noreply.github.com>

Author: otelbot[bot]

instrumentation/restlet/restlet-2.0/testing/src/main/java/io/opentelemetry/instrumentation/restlet/v2_0/spring/AbstractSpringServerTest.java

@@ -10,23 +10,32 @@
 import org.restlet.Component;
 import org.restlet.Server;
 import org.restlet.routing.Router;
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 
 public abstract class AbstractSpringServerTest extends AbstractRestletServerTest {
 
   protected Router router;
+  private ClassPathXmlApplicationContext context;
 
   protected abstract String getConfigurationName();
 
   @Override
   protected void setupServer(Component component) {
-    ApplicationContext context = new ClassPathXmlApplicationContext(getConfigurationName());
+    context = new ClassPathXmlApplicationContext(getConfigurationName());
     router = (Router) context.getBean("testRouter");
     Server server = (Server) context.getBean("testServer", "http", port);
     component.getServers().add(server);
   }
 
+  @Override
+  protected void stopServer(Component component) throws Exception {
+    try {
+      super.stopServer(component);
+    } finally {
+      context.close();
+    }
+  }
+
   @Override
   protected void setupRouting() {
     attach(router);