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3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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23 
24 package test.java.util.Random;
25 
26 import jdk.test.lib.RandomFactory;
27 
28 /**
29  * @test
30  * @summary Check that nextExponential() returns non-negative outcomes
31  * @bug 8284866
32  *
33  * @key randomness
34  * @library /test/lib
35  * @build jdk.test.lib.RandomFactory
36  * @run main RandomExponentialTest
37  */
38 
39 public class RandomExponentialTest {
40 
41     // Android-changed: reduce number of iterations as it takes too much time to finish
42     // on certain devices / targets.
43     // private static final int SAMPLES = 1_000_000_000;
44     private static final int SAMPLES = 40_000_000;
45 
main(String[] args)46     public static void main(String[] args) throws Exception {
47         var errCount = 0;
48         var errSample = Double.NaN;
49         var random = RandomFactory.getRandom();
50         for (int i = 0; i < SAMPLES; i++) {
51             var expVal = random.nextExponential();
52             if (!(expVal >= 0.0)) {
53                 errCount += 1;
54                 errSample = expVal;
55             }
56         }
57         if (errCount > 0) {
58             throw new RuntimeException("%d errors out of %d samples: e.g., %f"
59                             .formatted(errCount, SAMPLES, errSample));
60         }
61     }
62 
63 }
64