added ex S2

src/exercises/ex_s2/TestingAtomicInteger.java

@@ -0,0 +1,42 @@
+package exercises.ex_s2;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicIntegerArray;
+
+public class TestingAtomicInteger {
+    public static void main(String[] args) throws InterruptedException {
+        int[] nonAtomic = new int[5];
+        AtomicIntegerArray atomic = new AtomicIntegerArray(5);
+
+        for (int i = 0; i < 5; i++) {
+            nonAtomic[i] = i;
+            atomic.set(i, i);
+        }
+
+        System.out.println("Starting values atomic array: " + atomic);
+        System.out.println("Starting values of non atomic array: " + Arrays.toString(nonAtomic));
+        System.out.println("Creating 3 threads to increment the values within those two arrays");
+
+        Thread[] threads = new Thread[3];
+        for (int i = 0; i < 3; i++) {
+            threads[i] = new Thread(() -> {
+                for (int j = 0; j < 100000; j++) {
+                    for (int k = 0; k < 5; k++) {
+                        nonAtomic[k] += 1;
+                        atomic.incrementAndGet(k);
+                    }
+                }
+            });
+            threads[i].start();
+        }
+
+        for (int i = 0; i < 3; i++) {
+            threads[i].join();
+        }
+
+        System.out.println("Final values atomic array: " + atomic);
+        System.out.println("Final values of non atomic array: " + Arrays.toString(nonAtomic));
+    }
+}