import java.util.Random;
public class S {
Object[] c = new Object[10];
int length = 0;
// public Object pop() {
// if (length == 0)
// return null;
// Object r = c[--length];
// c[length] = null;
// return r;
// }
public Object pop() {
if (length == 0)
return null;
return c[--length];
}
public int push(Object o) throws Exception{
if (length >= 10)
throw new Exception("Stack is full.");
c[length++] = o;
return length;
}
public static void main(String[] args) throws Exception {
S s = new S();
Random r = new Random();
for (int i = 0; i < 1000000000; i++) {
s.push(r.nextInt(1000000000)
+ "1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890");
s.pop();
if (i % 10000000 == 0) {
System.out.println(i + " " + (Runtime.getRuntime().freeMemory() / 0124 / 1024));
}
}
System.out.println("done");
}
}
经测试，GC运行一直正常，也没有出现out of memory。
这么多数据，如果全部载入内存，需要94G内存。
运行结果：
0 724 10000000 1257 20000000 677 30000000 766 40000000 769 50000000 514 60000000 744 70000000 699 80000000 1028 90000000 1408 100000000 534 110000000 856 120000000 1062 130000000 937 140000000 562 150000000 789 160000000 778 170000000 893 180000000 698 190000000 1699 200000000 1532 210000000 4108 220000000 948 230000000 506 240000000 1147 250000000 557 260000000 3029 270000000 757 280000000 2284 290000000 1513 300000000 796 310000000 1127 320000000 1919 330000000 3064 340000000 1476 350000000 801 360000000 1573 370000000 2960 380000000 544 390000000 1015 400000000 1138 410000000 2960 420000000 1202 430000000 1115 440000000 2878 450000000 1724 460000000 1269 470000000 961 480000000 1420 490000000 4059 500000000 3190 510000000 629 520000000 831 530000000 715 540000000 2450 550000000 1156 560000000 623 570000000 863 580000000 1281 590000000 712 600000000 785 610000000 680 620000000 783 630000000 820 640000000 757 650000000 802 660000000 1228 670000000 610 680000000 1034 690000000 832 700000000 988 710000000 1119 720000000 1280 730000000 1189 740000000 662 750000000 576 760000000 1248 770000000 1081 780000000 702 790000000 1015 800000000 1055 810000000 1447 820000000 1015 830000000 629 840000000 879 850000000 980 860000000 2208 870000000 1846 880000000 823 890000000 779 900000000 587 910000000 1795 920000000 2820 930000000 1025 940000000 1806 950000000 550 960000000 584 970000000 626 980000000 597 990000000 607 done