问题描述
调用newInstance（）是否会受到惩罚，或者下面的机制是否相同？
newInstance（）对新关键字*有多少开销？
Is there a penalty for calling newInstance() or is it the same mechanism underneath?How much overhead if any does newInstance() have over the new keyword* ?
*：折扣newInstance（）暗示使用反射这一事实。
*: Discounting the fact that newInstance() implies using reflection.
推荐答案
在现实世界的测试中，通过Constuctor.newInstance创建一个类的18129个实例，传递10个参数-vs-创建实例通过新程序在时间上没有产生可测量的差异。
In a real world test, creating 18129 instances of a class via "Constuctor.newInstance" passing in 10 arguments -vs- creating the instances via "new" the program took no measurable difference in time.
这不是任何微观基准。
这是在Windows 7 x86 beta上的JDK 1.6.0_12。
This is with JDK 1.6.0_12 on Windows 7 x86 beta.
鉴于Constructor.newInstance将与Class.forName.newInstance非常相似我会说使用newInstance而不是新功能可以获得的开销很少。
Given that Constructor.newInstance is going to be very simlilar to Class.forName.newInstance I would say that the overhead is hardly anything given the functionality that you can get using newInstance over new.
一如既往，你应该自己测试看看。
As always you should test it yourself to see.
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