Verification in agent transformers

[Ryan Ernst]

This is load time instrumentation. Once we’ve registered our transformer, we look at what classes have already been loaded, and force retransformation of those. The error only occurred when the class in question was loaded before our (dynamic) agent ran.

> On Mar 7, 2025, at 10:42 AM, Alan Bateman <Alan.Bateman at oracle.com> wrote:
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> On 07/03/2025 17:28, Ryan Ernst wrote:
>> When the transformer runs outside of retransformClasses, there is no VerifyError, yet the incompatible type existed (but it was unused, so did not trip a runtime problem, it was just a bad type sitting on the stack).
>> 
> 
> What does "outside of retransformClasses" mean? Is this static instrumentation where classes in modules mapped to the boot loader are instrumented and the jimage re-created with the modified classes, or is this load time instrumentation?
> 
> -Alan