ATTACH.md

Dynamic Attach (Agent_OnAttach)

This crate supports dynamic attach via the Agent_OnAttach entry point. Implement Agent::on_attach and use export_agent! — the macro generates the correct native entry points automatically.

Minimal Example

use jvmti_bindings::prelude::*;

#[derive(Default)]
struct AttachLogger;

impl Agent for AttachLogger {
    fn on_attach(&self, vm: *mut jni::JavaVM, options: &str) -> jni::jint {
        println!("[AttachLogger] attached with options: {}", options);
        let _jvmti = Jvmti::new(vm).expect("get JVMTI");
        jni::JNI_OK
    }
}

export_agent!(AttachLogger);

Notes

• on_attach is called when the agent is loaded via the JVM Attach API.
• You can request capabilities and enable JVMTI events inside on_attach.
• Thread and JNI safety rules still apply (see docs/SAFETY.md).