Test Java primitive int vs wrapper Integer speed and memory usage

JavaArrayTest.java

import java.lang.management.ManagementFactory;
import java.lang.management.MemoryMXBean;

/**
 * Class Name: Test
 * Purpose: Test primitive int vs wrapper Integer speed and memory usage
 */
public class JavaArrayTest {
    /**
     * Method Name: main
     * Method Description: Main method for Test
     * @param args (not used)
     */
    public static void main(String[] args) {
        // declare variables and objects
        MemoryMXBean memoryBean = ManagementFactory.getMemoryMXBean();
        long beforeUsedMem, startTime, endTime, afterUsedMem;
        int size = 10_000_000;

        // Test 1 with primitive int
        beforeUsedMem = memoryBean.getHeapMemoryUsage().getUsed();
        startTime = System.nanoTime();

        int[] arrInt = new int[size];
        for (int i = 0; i < size; i++) {
            arrInt[i] = i;
        }

        endTime = System.nanoTime();
        afterUsedMem = memoryBean.getHeapMemoryUsage().getUsed();

        System.out.println("\nPrimitive int array");
        System.out.println("Time taken in milliseconds: " + (endTime - startTime) / 1_000_000);
        System.out.println("Memory used in bytes: " + (afterUsedMem - beforeUsedMem));

        // Test 1 with wrapper Integer
        beforeUsedMem = memoryBean.getHeapMemoryUsage().getUsed();
        startTime = System.nanoTime();

        Integer[] arrInteger = new Integer[size];
        for (int i = 0; i < size; i++) {
            arrInteger[i] = i;
        }

        endTime = System.nanoTime();
        afterUsedMem = memoryBean.getHeapMemoryUsage().getUsed();

        System.out.println("\nWrapper Integer array");
        System.out.println("Time taken in milliseconds: " + (endTime - startTime) / 1_000_000);
        System.out.println("Memory used in bytes: " + (afterUsedMem - beforeUsedMem));


        // Test 2 with wrapper Integer
        beforeUsedMem = memoryBean.getHeapMemoryUsage().getUsed();
        startTime = System.nanoTime();

        Integer[] arrInteger2 = new Integer[size];
        for (int i = 0; i < size; i++) {
            arrInteger2[i] = i;
        }

        endTime = System.nanoTime();
        afterUsedMem = memoryBean.getHeapMemoryUsage().getUsed();

        System.out.println("\nWrapper Integer array");
        System.out.println("Time taken in milliseconds: " + (endTime - startTime) / 1_000_000);
        System.out.println("Memory used in bytes: " + (afterUsedMem - beforeUsedMem));

        // Test 2 with primitive int
        beforeUsedMem = memoryBean.getHeapMemoryUsage().getUsed();
        startTime = System.nanoTime();

        int[] arrInt2 = new int[size];
        for (int i = 0; i < size; i++) {
            arrInt2[i] = i;
        }

        endTime = System.nanoTime();
        afterUsedMem = memoryBean.getHeapMemoryUsage().getUsed();

        System.out.println("\nPrimitive int array");
        System.out.println("Time taken in milliseconds: " + (endTime - startTime) / 1_000_000);
        System.out.println("Memory used in bytes: " + (afterUsedMem - beforeUsedMem));
    } // end method main
} // end class Test