parallel stream with unboxing

spdpiyush · spdpiyush · commit ce32ecce7618 · 2025-03-10T14:20:41.000+05:30
diff --git a/Modern-Java-Examples/src/com/learn/parallelstream/ParallelStreamBoxedExample.java b/Modern-Java-Examples/src/com/learn/parallelstream/ParallelStreamBoxedExample.java
@@ -0,0 +1,57 @@
+package com.learn.parallelstream;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * <p>
+ *     It is always recommended to check the performance before
+ *     going to the assumption that parallel stream is going to perform better.
+ * </p>
+ */
+public class ParallelStreamBoxedExample {
+
+    public static void main(String[] args) {
+
+        /**
+         * This are not primitive integers.
+         * These are Wrapper integer Objects.
+         */
+        List<Integer> integerList = IntStream.rangeClosed(1, 10000).boxed().collect(Collectors.toList());
+        sequentialSum(integerList);
+        parallelSum(integerList);
+    }
+
+
+    /**
+     * <p>
+     *     Performing the Sequential Stream on the input.
+     * </p>
+     */
+    public static int sequentialSum(List<Integer> integerList) {
+        long startTime = System.currentTimeMillis();
+        int sum =  integerList
+                .stream()
+                .reduce(0, Integer::sum);
+        long endTime = System.currentTimeMillis();
+        System.out.println("Sequential Stream Time Take : " + (endTime - startTime));
+        return sum;
+    }
+
+    /**
+     * <p>
+     *     Performing the parallel Stream on the input.
+     *     here, it need to convert unboxing from Integer to int for each and every value.
+     * </p>
+     */
+    public static int parallelSum(List<Integer> integerList) {
+        long startTime = System.currentTimeMillis();
+        int sum = integerList
+                .parallelStream()
+                .reduce(0, Integer::sum); // here effort is required to perform Unboxing.
+        long endTime = System.currentTimeMillis();
+        System.out.println("Parallel Stream Time Taken : " + (endTime - startTime));
+        return sum;
+    }
+}
diff --git a/README.md b/README.md
@@ -54,6 +54,7 @@ This repository contains the basic &amp; advance level examples related to Java
   * parallelStream 
       * [ parallel Stream Example & Performance](Modern-Java-Examples/src/com/learn/parallelstream/ParallelStreamExample.java)
       * [ sequential & parallel Stream Comparison ](Modern-Java-Examples/src/com/learn/parallelstream/ParallelStreamExample1.java)
+      * [ sequential & parallel stream unboxing Performance ](Modern-Java-Examples/src/com/learn/parallelstream/ParallelStreamBoxedExample.java)
 
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