add a stream example

fishercoder1534 · fishercoder1534 · commit a38ef41c0f7e · 2024-02-05T08:59:33.000-08:00
diff --git a/src/main/java/java_streams/StreamsExample.java b/src/main/java/java_streams/StreamsExample.java
@@ -0,0 +1,43 @@
+package java_streams;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class StreamsExample {
+    public static void main(String... args) {
+        /**reference: https://www.baeldung.com/java-when-to-use-parallel-stream*/
+        System.out.println("Program started.");
+        sequentialStreams();
+        parallelStreams();
+        System.out.println("Program ended.");
+    }
+
+    private static void sequentialStreams() {
+        /**By default, any stream operation in Java is processed sequentially, unless explicitly specified as parallel.
+         Sequential streams use a single thread to process the pipeline like below:
+         */
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        listOfNumbers.stream().forEach(number ->
+                System.out.println(number + " from this thread: " + Thread.currentThread().getName())
+        );
+    }
+
+    private static void parallelStreams() {
+        /**
+         * Any stream in Java can easily be transformed from sequential to parallel.
+         * We can achieve this by adding the parallel method to a sequential stream or by creating a stream using the parallelStream method of a collection:
+         * */
+        List<Integer> listOfNumbers = Arrays.asList(5, 6, 7, 8);
+        listOfNumbers.parallelStream().forEach(number ->
+                System.out.println(number + " from this thread: " + Thread.currentThread().getName())
+        );
+        /**
+         * Parallel streams enable us to execute code in parallel on separate cores.
+         * The final result is the combination of each individual outcome.
+         * However, the order of execution is out of our control.*/
+
+        /**
+         * Parallel streams make use of the fork-join framework and its common pool of worker threads.
+         * The fork-join framework was added to java.util.concurrent in Java 7 to handle task management between multiple threads.*/
+    }
+}
