Java中一个空体的循环 [英] A loop with an empty body in Java

问题描述

  void waiter（ ）{
 for（int i = 0; i <20000; i ++）; 
 
 
 
 $ b $ p 
 $ b 
这会导致停顿一段时间，还是会被JVM优化忽略？ / p> 
 
解决方案
它将在JIT运行几次之后进行优化。 JVM在第一次运行时需要检查是否正在增加的值 i 没有被使用。
 
 
 
检查这篇文章：
 
 
  Java：一个空循环使用多少时间？ 
 
During bug fixing in very old project I've faced with strange method, it looks like this:
   void waiter() {
        for (int i = 0; i < 20000; i++) ;
    }
Does it cause halting some time or it will be omitted by JVM optimization?
解决方案
It will be optimized after few runs by JIT. The JVM , at the first run, needs to check if the value if i that is being incremented is not being used anywhere.

Check this article as well : 

Java: how much time does an empty loop use?

                        
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