Reduced warn log entry without stacktrace for startup exceptions

Also, AbstractApplicationContext.isRunning avoids IllegalStateException now.

Issue: SPR-13663
Issue: SPR-13667

Author: jhoeller

spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java

@@ -484,7 +484,10 @@ public void refresh() throws BeansException, IllegalStateException {
 			}
 
 			catch (BeansException ex) {
-				logger.warn("Exception encountered during context initialization - cancelling refresh attempt", ex);
+				if (logger.isWarnEnabled()) {
+					logger.warn("Exception encountered during context initialization - " +
+							"cancelling refresh attempt: " + ex);
+				}
 
 				// Destroy already created singletons to avoid dangling resources.
 				destroyBeans();
@@ -1182,7 +1185,7 @@ public void stop() {
 
 	@Override
 	public boolean isRunning() {
-		return getLifecycleProcessor().isRunning();
+		return (this.lifecycleProcessor != null && this.lifecycleProcessor.isRunning());
 	}