Unsafe and JPMS

[Alan Bateman]

On 20/01/2018 00:07, Jeremy Manson wrote:
> :
>
> The other place I saw that this came up is the cglib code generation 
> library, which now uses Unsafe to access ClassLoader.defineClass (for 
> any ClassLoader).  This is useful for generating classes for 
> dependency injection / mocking / that kind of thing.  It is a 
> violation of encapsulation, but it is done with a very specific 
> software engineering goal in mind.  It was never a terribly good 
> approach, but it a library that is now depended upon by a very large 
> amount of code in the wild.
>
DI and other cases with frameworks doing code injection should be 
looking at Lookup.defineClass. Frameworks can use this API to inject a 
class into an existing runtime package once they have a Lookup object 
with the appropriate access. it's not all use-cases but it's the only 
supported API in the platform for doing this kind of thing.

-Alan