Java uses more memory than anticipated

Ok, so I try to do this little experiment in java. I want to fill up a queue with integers and see how long it takes. Here goes:

import java.io.*;
import java.util.*;

class javaQueueTest {
public static void main(String args[]){
    System.out.println("Hello World!");
    long startTime = System.currentTimeMillis();
    int i;
    int N = 50000000;

    ArrayDeque<Integer> Q = new ArrayDeque<Integer>(N);
    for (i = 0;i < N; i = i+1){
        Q.add(i);
    }
    long endTime   = System.currentTimeMillis();
    long totalTime = endTime - startTime;
    System.out.println(totalTime);
}
}

OK, so I run this and get a

Hello World!
12396

About 12 secs, not bad for 50 million integers. But if I try to run it for 70 million integers I get:

Hello World!
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.lang.Integer.valueOf(Integer.java:642)
    at javaQueueTest.main(javaQueueTest.java:14)

I also notice that it takes about 10 mins to come up with this message. Hmm so what if I give almost all my memory (8gigs) for the heap? So I run it for heap size of 7gigs but I still get the same error:

javac javaQueueTest.java
java -cp . javaQueueTest -Xmx7g
Hello World!
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.lang.Integer.valueOf(Integer.java:642)
    at javaQueueTest.main(javaQueueTest.java:14)

I want to ask two things. First, why does it take so long to come up with the error? Second, Why is all this memory not enough ? If I run the same experiment for 300 million integers in C (with the glib g_queue) it will run (and in 10 secs no less! although it will slow down the computer alot) so the number of integers must not be at fault here. For the record, here is the C code:

#include<stdlib.h>
#include<stdio.h>
#include<math.h>
#include<glib.h>
#include<time.h>

int main(){
clock_t begin,end;
double time_spent;
GQueue *Q;

begin = clock();
Q = g_queue_new();
g_queue_init(Q);
int N = 300000000;
int i;
for (i = 0; i < N; i = i+1){
    g_queue_push_tail(Q,GINT_TO_POINTER(i));
}
end = clock();
time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
printf("elapsed time: %f \n",time_spent);

}

I compile and get the result:

gcc cQueueTest.c `pkg-config --cflags --libs glib-2.0 gsl ` -o cQueueTest
~/Desktop/Software Development/Tests $ ./cQueueTest 
elapsed time: 13.340000