一个简单的计算

public class Test {
public static void main(String[] args){
long start = System.currentTimeMillis();
long sum = 0L;
for(long i=0; i<Integer.MAX_VALUE; i++){
sum += i;
}
System.out.println(sum);
System.out.println(System.currentTimeMillis() - start);
}
}

public class Test {
public static void main(String[] args){
long start = System.currentTimeMillis();
Long sum = 0L;
for(long i=0; i<Integer.MAX_VALUE; i++){
sum += i;
}
System.out.println(sum);
System.out.println(System.currentTimeMillis() - start);
}
}