Test synchronized

Author: winterbe

src/com/winterbe/java8/samples/concurrent/ConcurrentUtils.java

@@ -0,0 +1,27 @@
+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class ConcurrentUtils {
+
+ public static void stop(ExecutorService executor) {
+ try {
+ executor.shutdown();
+ executor.awaitTermination(5, TimeUnit.SECONDS);
+ }
+ catch (InterruptedException e) {
+ System.err.println("termination interrupted");
+ }
+ finally {
+ if (!executor.isTerminated()) {
+ System.err.println("killing non-finished tasks");
+ }
+ executor.shutdownNow();
+ }
+ }
+
+}

src/com/winterbe/java8/samples/concurrent/Synchronized1.java

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+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.stream.IntStream;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Synchronized1 {
+
+ private static final int NUM_INCREMENTS = 10000;
+
+ private static int count = 1;
+
+ public static void main(String[] args) {
+ testSyncIncrement();
+ testNonSyncIncrement();
+ }
+
+ private static void testSyncIncrement() {
+ count = 1;
+
+ ExecutorService executor = Executors.newFixedThreadPool(2);
+
+ IntStream.range(0, NUM_INCREMENTS)
+ .forEach(i -> executor.submit(Synchronized1::incrementSync));
+
+ ConcurrentUtils.stop(executor);
+
+ System.out.println(" Sync: " + count);
+ }
+
+ private static void testNonSyncIncrement() {
+ count = 1;
+
+ ExecutorService executor = Executors.newFixedThreadPool(2);
+
+ IntStream.range(0, NUM_INCREMENTS)
+ .forEach(i -> executor.submit(Synchronized1::increment));
+
+ ConcurrentUtils.stop(executor);
+
+ System.out.println("NonSync: " + count);
+ }
+
+ private static synchronized void incrementSync() {
+ count = count + 1;
+ }
+
+ private static void increment() {
+ count = count + 1;
+ }
+}