java.util.Arrays.sort() - Performance

This section provides a tutorial on how to measure the performance of the java.util.Arrays.sort() function provided by JDK.

Before implementing my own versions of different sorting algorithms, I used the test program, SortTest.java, to get some performance results with the java.util.Arrays.sort() function provided by JDK 13. Here are the results:

Array size: 100000
Average sorting time: 25 milliseconds
Number of tests: 1000
Performance: 0.25 O(N) microseconds
Performance: 0.015051499783199059 O(N*Log2(N)) microseconds
Performance: 2.5E-6 O(N*N) microseconds

Array size: 200000
Average sorting time: 66 milliseconds
Number of tests: 1000
Performance: 0.33 O(N) microseconds
Performance: 0.018739735230770178 O(N*Log2(N)) microseconds
Performance: 1.65E-6 O(N*N) microseconds

Array size: 300000
Average sorting time: 112 milliseconds
Number of tests: 1000
Performance: 0.37333333333333335 O(N) microseconds
Performance: 0.020518905185403863 O(N*Log2(N)) microseconds
Performance: 1.2444444444444445E-6 O(N*N) microseconds

The result was very impressive. I had to increase the array size to 100,000 to get the performance measurements. As you can see, the performance is close to the order of O(N*Log2(N)).

As a reference, results from an older computer with an older JDK version are listed below:

Array size: 10000
Average sorting time: 17 milliseconds
Number of tests: 1000
Performance: 1.7 O(N) microseconds
Performance: 0.127937748157192 O(N*Log2(N)) microseconds
Performance: 1.7E-4 O(N*N) microseconds

Array size: 20000
Average sorting time: 45 milliseconds
Number of tests: 1000
Performance: 2.25 O(N) microseconds
Performance: 0.1574779740961549 O(N*Log2(N)) microseconds
Performance: 1.125E-4 O(N*N) microseconds

Array size: 30000
Average sorting time: 70 milliseconds
Number of tests: 1000
Performance: 2.3333333333333335 O(N) microseconds
Performance: 0.15688726823636978 O(N*Log2(N)) microseconds
Performance: 7.777777777777778E-5 O(N*N) microseconds

Table of Contents

 About This Book

 Introduction of Sorting Algorithms

Java API for Sorting Algorithms

 Why Java API Is Needed

 HyObject.java - Data Element Class

 SortTest.java - Testing Program

java.util.Arrays.sort() - Performance

 Performance Summary of Java Implementations

 Insertion Sort Algorithm and Java Implementation

 Selection Sort Algorithm and Java Implementation

 Bubble Sort Algorithm and Java Implementation

 Quicksort Algorithm and Java Implementation

 Merge Sort Algorithm and Java Implementation

 Heap Sort Algorithm and Java Implementation

 Shell Sort Algorithm and Java Implementation

 Sorting Algorithms Implementations in PHP

 Sorting Algorithms Implementations in Perl

 Sorting Algorithms Implementations in Python

 Performance Summary of All Implementations

 References

 Full Version in PDF/EPUB