Time for creating big arrays

Question

Hi,
My program needed to create several arrays with big size and I found a interesting phenomenon:
int capacityI=13000000;
time1=System.currentTimeMillis();
int[] v1=new int[13000000];
time2=System.currentTimeMillis();
int[] v2=new int[13000000];
long time3=System.currentTimeMillis();
int[] v3=new int[13000000];
long time4=System.currentTimeMillis();
int[] v4=new int[13000000];
long time5=System.currentTimeMillis();
int[] v5=new int[13000000];
long time6=System.currentTimeMillis();
System.out.println(time2-time1);
System.out.println(time3-time2);
System.out.println(time4-time3);
System.out.println(time5-time4);
System.out.println(time6-time5);And following is an output of the program:
15
16
16
5625
16
it took much more time to create the fourth array and I could not find the reason. My program is a big program, It did many things before the execution of the above code. Was it related to the garbage collector? I meant the java system ran the garbage collection program before the creation the the fourth array. Was I right?
I want to prevent this problem, i.e., decrese the time for the creation of arrays. Is there any way?
Thanks.

Answer 1

Note that your snippet of test code doe snot require the 5 arrays to be in memory at the same time and is hence not representing your later stated requirement to have them all available.
Your locally created v1 array is not referenced anymore after creation and therefore eligible for garbage collection, be aware of that. Setting good initial and maximum heap size values as suggested by others is of importance here.