计算Java启动成本 [英] Calculate Java start up cost

问题描述

我目前有一个程序，可以在其中打印运行 main 方法所需的时间.然而，当我在命令行上运行这个程序并计时时，它需要更长的时间.

I currently have a program in which I can print how long it takes to run the main method. When I run this program on command line and time it however, it takes considerably longer.

例如，

$ time java MyProgram "arg"
done by .004

real    0m0.105s
user    0m0.083s
sys     0m0.022s

我的问题是 - 是否可以在程序本身内计算 java 程序的启动成本?

My question is this- is it possible to calculate the start up cost of the java program within the program itself?

推荐答案

你可以把它作为你的 main 方法的第一行.java.lang.management.ManagementFactory.getRuntimeMXBean().getUptime()

You could put this as the first line in your main method. java.lang.management.ManagementFactory.getRuntimeMXBean().getUptime()

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