added volatile veriable and synchronizated to method

Author: StarAntonU

src/main/java/core/basesyntax/Counter.java

@@ -6,13 +6,13 @@
 public class Counter {
     private static final Logger logger = LogManager.getLogger(Counter.class);
     private static final String MESSAGE = "%20s, Thread # %2s, counter value %2d";
-    private int value;
+    private volatile int value;
 
     public Counter(int value) {
         this.value = value;
     }
 
-    public void decreaseValue() {
+    public synchronized void decreaseValue() {
         logger.info(String.format(MESSAGE,
                 "Before decrementing", Thread.currentThread().getName(), value));
         value--;