Get callbacks working

java/patchbukkit/src/main/java/org/patchbukkit/NativeCallbacks.java

@@ -1,5 +1,34 @@
 package org.patchbukkit;
 
 import org.astonbitecode.j4rs.api.invocation.NativeCallbackToRustChannelSupport;
+import org.bukkit.event.Listener;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
 
-public class NativeCallbacks extends NativeCallbackToRustChannelSupport {}
+public class NativeCallbacks extends NativeCallbackToRustChannelSupport {
+
+    private static NativeCallbacks instance;
+
+    public NativeCallbacks() {
+        NativeCallbacks.setInstance(this);
+    }
+
+    private static synchronized void setInstance(
+        NativeCallbacks nativeCallbacks
+    ) {
+        if (instance == null) {
+            instance = nativeCallbacks;
+        }
+    }
+
+    public static NativeCallbacks getInstance() {
+        return instance;
+    }
+
+    public void doRegisterCallback(
+        @NotNull Listener listener,
+        @NotNull Plugin plugin
+    ) {
+        doCallback(new Object[] { listener, plugin });
+    }
+}

java/patchbukkit/src/main/java/org/patchbukkit/PatchBukkitPluginManager.java

@@ -98,9 +98,7 @@ public class PatchBukkitPluginManager implements PluginManager {
         @NotNull Listener listener,
         @NotNull Plugin plugin
     ) {
-        throw new UnsupportedOperationException(
-            "Unimplemented method 'registerEvents'"
-        );
+        NativeCallbacks.getInstance().doRegisterCallback(listener, plugin);
     }
 
     @Override

rust/src/lib.rs

@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use j4rs::Jvm;
+use j4rs::{InvocationArg, Jvm};
 use pumpkin::plugin::Context;
 use pumpkin_api_macros::{plugin_impl, plugin_method};
 
@@ -75,6 +75,31 @@ async fn on_load_inner(plugin: &mut PatchBukkitPlugin, server: Arc<Context>) ->
     let jvm = initialize_jvm(&dirs.j4rs)?;
     setup_patchbukkit_server(&jvm)?;
 
+    let i = jvm
+        .create_instance("org.patchbukkit.NativeCallbacks", InvocationArg::empty())
+        .map_err(|err| err.to_string())?;
+    let r = jvm.init_callback_channel(&i).unwrap();
+
+    std::thread::spawn(move || {
+        if let Err(e) = Jvm::attach_thread() {
+            log::error!("Failed to attach callback thread to JVM: {}", e);
+            return;
+        }
+
+        loop {
+            match r.rx().recv() {
+                Ok(ret) => {
+                    plugin.plugin_manager.add_listener();
+                    log::info!("Received callback: {:?}", ret.class_name());
+                }
+                Err(e) => {
+                    log::error!("Callback channel closed: {}", e);
+                    break;
+                }
+            }
+        }
+    });
+
     plugin
         .plugin_manager
         .load_all_plugins(&jvm)