原文地址： https://caoxudong818.iteye.com/blog/1150293
今天一同事说到java的运行效率是js的10倍。吾深感好奇，差这么多吗？遂写个小程序试一下，程序只是循环加1，但是在运行过程中会有执行时间大大增加的时候出现，无论java或是js都是这样。搞不清究竟是什么原因，请高人指点。 先贴上本机配置。
Intel(R) Core(TM)2 Quard CPU
Q8400 @ 2.66GHz
2.66 GHz , 1.98 GB 的内存。
E:\Workspace\java\test> java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) Client VM (build 20.1-b02, mixed mode, sharing)
浏览器使用了chrome12和chrome8的两个版本。 先上代码。
public class Test {
public static void main(String[] args) {
int i=0,j=0,k=0;
long beginTime=0,endTime=0,interval=0 ;
StringBuilder result = new StringBuilder() ;
for(i=0;i<1000;i++){
beginTime = System.currentTimeMillis() ;
for(j=0;j<1000000;j++){
k++ ;
}
endTime = System.currentTimeMillis() ;
interval = endTime - beginTime ;
result.append("cost ") ;
result.append(interval) ;
result.append(" milliseconds") ;
System.out.println(result.toString()) ;
result.delete(0,result.length()) ;
}
}
}
然后是执行结果，先是java的：
cost 0 milliseconds
cost 0 milliseconds
cost 16 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 15 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 16 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
js的执行结果： chrome12的执行结果
cost 14 milliseconds
cost 14 milliseconds
cost 14 milliseconds
cost 10 milliseconds
cost 4 milliseconds
cost 3 milliseconds
cost 3 milliseconds
cost 4 milliseconds
cost 4 milliseconds
cost 3 milliseconds
cost 4 milliseconds
cost 3 milliseconds
cost 3 milliseconds
cost 4 milliseconds
chrome8的执行结果
cost 15 milliseconds
cost 15 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 16 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 15 milliseconds
cost 16 milliseconds
cost 0 milliseconds
cost 15 milliseconds
cost 0 milliseconds
cost 16 milliseconds
cost 0 milliseconds
cost 0 milliseconds
cost 0 milliseconds
问题：为什么java和chrome8在运行过程中会有计算时间突然加长的时候？ 坐等高人。