Fixed busy waiting in points 1,2,3,7 (1)

Author: alhusseain

queue-based-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/MessageQueue.java

@@ -36,7 +36,7 @@
 public class MessageQueue {
 
   private final BlockingQueue<Message> blkQueue;
-  public Object serviceExecutorWait=new Object();
+  public final Object serviceExecutorWait=new Object();
 
   // Default constructor when called creates Blocking Queue object. 
   public MessageQueue() {

server-session/pom.xml

@@ -49,17 +49,4 @@
             <scope>test</scope>
         </dependency>
     </dependencies>
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>8</source>
-                    <target>8</target>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-
 </project>

server-session/src/main/java/com/iluwatar/sessionserver/App.java

@@ -59,7 +59,7 @@ public class App {
   private static Map<String, Integer> sessions = new HashMap<String,Integer>();
   private static Map<String, Instant> sessionCreationTimes = new HashMap<String,Instant>();
   private static final long SESSION_EXPIRATION_TIME = 10000;
-  private static Object sessionExpirationWait=new Object(); // used to make expiration task wait or work based on event (login request sent or not)
+  private static final Object sessionExpirationWait=new Object(); // used to make expiration task wait or work based on event (login request sent or not)
 
   /**
    * Main entry point.
@@ -89,11 +89,11 @@ private static void sessionExpirationTask() {
         try {
           synchronized (sessions)
           {
-            if(sessions.isEmpty())
-            synchronized (sessionExpirationWait)
-            {
-              sessionExpirationWait.wait(); // Make Session expiration Checker wait until at least a single login request is sent.
-            }
+              if(sessions.isEmpty())
+              synchronized (sessionExpirationWait)
+              {
+                sessionExpirationWait.wait(); // Make Session expiration Checker wait until at least a single login request is sent.
+              }
           }
           LOGGER.info("Session expiration checker started...");
           Thread.sleep(SESSION_EXPIRATION_TIME); // Sleep for expiration time

twin/README.md

@@ -90,7 +90,7 @@ public class BallThread extends Thread {
 
   private volatile boolean isRunning = true;
 
-  private Object lock=new Object();
+  private final Object lock=new Object();
 
   /**
    * Run the thread.

twin/src/main/java/com/iluwatar/twin/BallThread.java

@@ -42,7 +42,7 @@ public class BallThread extends Thread {
 
   private volatile boolean isRunning = true;
 
-  private Object lock=new Object();
+  private final Object lock=new Object();
 
   /**
    * Run the thread.