newInstance() vs new

Question

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* ?

*: Discounting the fact that newInstance() implies using reflection.

Answer 1

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.

This wasn't any sort of micro benchmark.

This is with JDK 1.6.0_12 on Windows 7 x86 beta.

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.

As always you should test it yourself to see.