use sleep instead of Thread.yield to proper block

src/main/java/ch/cern/tdaq/cassandra/AALEngine.java

@@ -148,13 +148,16 @@ public final class AALEngine {
 				 * there is basic initialization, specifically the ConfigReader initialization.
 				 * We need to do that before the directives are loaded.
 				 */
+				log.info("Configuring ESPER in Replay mode, calling replay.ReplayInjector constructor");
 				replayInjectorInstance = (Injector)(Class.forName("ch.cern.tdaq.cassandra.replay.ReplayInjector")).newInstance();
+				log.info("ReplayInjector constructed, continue with ESPER configuration");
+				// ReplayInjector may throw RuntimeException, catch all that in Main, no way to continue
 			} catch (ClassNotFoundException e) {
-				e.printStackTrace();
+				throw new RuntimeException(e) ;
 			} catch (InstantiationException e) {
-				e.printStackTrace();
+				throw new RuntimeException(e) ;
 			} catch (IllegalAccessException e) {
-				e.printStackTrace();
+				throw new RuntimeException(e) ;
 			}
 		}
 
@@ -162,13 +165,14 @@ public final class AALEngine {
 		/**
 		 * Creating an RDB or an OKS configuration
 		 */
+		log.info("Loading OKS/RDB directives configuration: " + configuration.getRDBConfig());
 		db = new config.Configuration(configuration.getRDBConfig());	
 		AALSchema = new Schema(db);
 		
 		/**
 		 * Setting up basic statements
 		 */
-		log.info("Creating initial statements... ");
+		log.info("Registering initial statements... ");
 		esper.registerStatementsFromDatabase(AALSchema);
 
 		ConfigurationEvent c = new ConfigurationEvent("INIT");
@@ -216,8 +220,6 @@ public final class AALEngine {
 		}
 
 		log.info("Configuration phase done.");
-
-
 	}
 
 
@@ -323,8 +325,12 @@ public final class AALEngine {
          */
         periodicScheduler.scheduleWithFixedDelay(IScheck, 0, 10, SECONDS);
 
-		log.trace("Waiting forever...");
-		Thread.yield();
+		log.info("Waiting forever...");
+
+		try { Thread.sleep(Long.MAX_VALUE); }
+		catch ( final InterruptedException ex ) {} ;
+
+		log.info("Forever finished...");
 
 //		while (true) {
 //
@@ -345,7 +351,7 @@ public final class AALEngine {
 //
 
 
-	}
+	} // start()
 
 	public void shutdown() {
 
@@ -366,6 +372,7 @@ public final class AALEngine {
 
 		//Destroy the engine thread pools used for inbound and outbound processing
 		CEPProvider.getInstance().stop();
+		log.info("Shutdown completed");
 	}
 
 	public String getRootWriter() {