--- /dev/null	2013-12-19 08:49:00.325079479 +0800
+++ new/src/share/sample/demo/parallel/MonteCarloPI.java	2013-12-19 20:23:23.663082888 +0800
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ *   - Neither the name of Oracle nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This source code is provided to illustrate the usage of a given feature
+ * or technique and has been deliberately simplified. Additional steps
+ * required for a production-quality application, such as security checks,
+ * input validation and proper error handling, might not be present in
+ * this sample code.
+ */
+package demo.parallel;
+
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.stream.LongStream;
+
+/**
+ * This demo shows how to use the parallel mode and the Monte Carlo method to
+ * calculate the value of PI
+ *
+ * @author tyan
+ */
+public class MonteCarloPI {
+
+    public static void main(String[] args) {
+        System.out.println("This might take several minutes, "
+                + "depending on your system");
+        LongStream.iterate(10l, l -> 10 * l).
+                limit(10).
+                forEach(times -> {
+                    System.out.printf(
+                            "The value of PI is %1.14f after %,d times calculation\n",
+                            pi(times), times);
+                });
+    }
+
+    /**
+     * Use the Monte Carlo method to calculate the value of PI. basic algorithm
+     * is: 1. Draw a square on the ground, then inscribe a circle within it. 2.
+     * Scatter some objects of uniform size (grains of rice or sand) over the
+     * square. 3. Count the total number of objects inside the circle and the
+     * total number of objects overall. 4. The ratio of the two total is an
+     * estimate of the ratio of the two areas, which is PI/4. Multiply the
+     * result by 4 to estimate PI.
+     *
+     * @param x how many times randomly selected a point
+     * @return value of π by x times calculation
+     */
+    private static double pi(long x) {
+        return LongStream.generate(() -> hit()).
+                // using parallel mode
+                parallel().
+                // select only x elements
+                limit(x).sum()
+                // perform division before multiplication to reduce ovefflow 
+                // risk
+                / (double) x * 4;
+    }
+
+    /**
+     * Use ThreadLocalRandom to simulate that whether a point is inside the
+     * circle or outside the circle
+     *
+     * @return 1 randomly selected point is inside the circle 0 randomly
+     * selected point is outside the circle
+     */
+    private static long hit() {
+        ThreadLocalRandom lr = ThreadLocalRandom.current();
+        double x = lr.nextDouble(1.0);
+        double y = lr.nextDouble(1.0);
+        return Math.sqrt(y * y + x * x) <= 1.0 ? 1 : 0;
+    }
+}