Why is this C++ code execution so slow compared to java?

I recently wrote a computation-intensive algorithm in Java, and then translated it to C++. To my surprise the C++ executed considerably slower. I have now written a much shorter Java test program, and a corresponding C++ program - see below. My original code featured a lot of array access, as does the test code. The C++ takes 5.5 times longer to execute (see comment at end of each program).

Conclusions after 1^st 21 comments below ...

Test code:

1. g++ -o ... Java 5.5 times faster
2. g++ -O3 -o ... Java 2.9 times faster
3. g++ -fprofile-generate -march=native -O3 -o ... (run, then g++ -fprofile-use etc) Java 1.07 times faster.

My original project (much more complex than test code):

1. Java 1.8 times faster
2. C++ 1.9 times faster
3. C++ 2 times faster

Software environment:
    Ubuntu 16.04 (64 bit).
    Netbeans 8.2 / jdk 8u121 (java code executed inside netbeans)
    g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
    Compilation: g++ -o cpp_test cpp_test.cpp

Java code:

public class JavaTest {
    public static void main(String[] args) {
        final int ARRAY_LENGTH = 100;
        final int FINISH_TRIGGER = 100000000;
        int[] intArray = new int[ARRAY_LENGTH];
        for (int i = 0; i < ARRAY_LENGTH; i++) intArray[i] = 1;
        int i = 0;
        boolean finished = false;
        long loopCount = 0;
        System.out.println("Start");
        long startTime = System.nanoTime();
        while (!finished) {
            loopCount++;
            intArray[i]++;
            if (intArray[i] >= FINISH_TRIGGER) finished = true;
            else if (i <(ARRAY_LENGTH - 1)) i++;
            else i = 0;
        }
        System.out.println("Finish: " + loopCount + " loops; " +
            ((System.nanoTime() - startTime)/1e9) + " secs");
        // 5 executions in range 5.98 - 6.17 secs (each 9999999801 loops)
    }
}

C++ code:

//cpp_test.cpp:
#include <iostream>
#include <sys/time.h>
int main() {
    const int ARRAY_LENGTH = 100;
    const int FINISH_TRIGGER = 100000000;
    int *intArray = new int[ARRAY_LENGTH];
    for (int i = 0; i < ARRAY_LENGTH; i++) intArray[i] = 1;
    int i = 0;
    bool finished = false;
    long long loopCount = 0;
    std::cout << "Start\n";
    timespec ts;
    clock_gettime(CLOCK_REALTIME, &ts);
    long long startTime = (1000000000*ts.tv_sec) + ts.tv_nsec;
    while (!finished) {
        loopCount++;
        intArray[i]++;
        if (intArray[i] >= FINISH_TRIGGER) finished = true;
        else if (i < (ARRAY_LENGTH - 1)) i++;
        else i = 0;
    }
    clock_gettime(CLOCK_REALTIME, &ts);
    double elapsedTime =
        ((1000000000*ts.tv_sec) + ts.tv_nsec - startTime)/1e9;
    std::cout << "Finish: " << loopCount << " loops; ";
    std::cout << elapsedTime << " secs\n";
    // 5 executions in range 33.07 - 33.45 secs (each 9999999801 loops)
}