fix: use default impl if app context is not available in config facto…

…ry (#709)

Details: fixes the case when the web app context is not yet available for deployable WAR.

vaadin-spring/src/main/java/com/vaadin/flow/spring/SpringApplicationConfigurationFactory.java

@@ -16,14 +16,9 @@
 package com.vaadin.flow.spring;
 
 import java.util.Map;
-import java.util.concurrent.atomic.AtomicReference;
 
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.config.ConfigurableBeanFactory;
 import org.springframework.context.ApplicationContext;
-import org.springframework.context.annotation.Scope;
 import org.springframework.core.env.Environment;
-import org.springframework.stereotype.Component;
 import org.springframework.web.context.support.WebApplicationContextUtils;
 
 import com.vaadin.flow.server.VaadinContext;
@@ -41,20 +36,6 @@
 public class SpringApplicationConfigurationFactory
         extends DefaultApplicationConfigurationFactory {
 
-    @Component
-    @Scope(ConfigurableBeanFactory.SCOPE_SINGLETON)
-    private static class AppContextHolder {
-
-        @Autowired
-        private ApplicationContext context;
-
-        private static AtomicReference<AppContextHolder> self = new AtomicReference<>();
-
-        private AppContextHolder() {
-            self.set(this);
-        }
-    }
-
     @Override
     protected ApplicationConfigurationImpl doCreate(VaadinContext context,
             FallbackChunk chunk, Map<String, String> properties) {
@@ -65,10 +46,9 @@ protected ApplicationConfigurationImpl doCreate(VaadinContext context,
         ApplicationContext appContext = WebApplicationContextUtils
                 .getWebApplicationContext(servletContext.getContext());
         // sometimes for deployable WAR (couldn't find exact circumstances) the
-        // web app context is not yet available here, let's use a hack to get an
-        // app context from Spring singelton bean
+        // web app context is not yet available here
         if (appContext == null) {
-            appContext = AppContextHolder.self.get().context;
+            return super.doCreate(context, chunk, properties);
         }
         Environment env = appContext.getBean(Environment.class);
         // Collect any vaadin.XZY properties from application.properties