Borrowing one Example from JCIP

core-java-modules/core-java-concurrency-advanced/src/main/java/com/baeldung/concurrent/volatilekeyword/TaskRunner.java

@@ -0,0 +1,25 @@
+package com.baeldung.concurrent.volatilekeyword;
+
+public class TaskRunner {
+
+    private static int number;
+    private volatile static boolean ready;
+
+    private static class Reader extends Thread {
+
+        @Override
+        public void run() {
+            while (!ready) {
+                Thread.yield();
+            }
+
+            System.out.println(number);
+        }
+    }
+
+    public static void main(String[] args) {
+        new Reader().start();
+        number = 42;
+        ready = true;
+    }
+}