diff --git a/macros/src/java.rs b/macros/src/java.rs
index b73911d..d6e2f68 100644
--- a/macros/src/java.rs
+++ b/macros/src/java.rs
@@ -238,9 +238,9 @@ pub(super) fn java_method(attrs: TokenStream, input: TokenStream) -> TokenStream
 
     let class_token = if let Some(it) = type_bounds.iter().find(|i| i.0.to_string() == "Self") {
         let tt = it.1.clone();
-        quote! {<Self as #tt>::CLASS}
+        quote! {droid_wrap_utils::load_class(<Self as #tt>::CLASS)?}
     } else {
-        quote! {Self::CLASS}
+        quote! {droid_wrap_utils::load_class(Self::CLASS)?}
     };
 
     let ret_form = get_type_form(&ret_type, &None);
diff --git a/src/java/lang.rs b/src/java/lang.rs
index e69981c..39b20f8 100644
--- a/src/java/lang.rs
+++ b/src/java/lang.rs
@@ -389,7 +389,10 @@ pub fn test() {
     System::gc();
     let cl = ClassLoader::null().unwrap();
     assert_eq!(cl, ClassLoader::null().unwrap());
-    let func = RunnableImpl::from_fn(move || println!("Runnable is running."));
+    let func = RunnableImpl::from_fn(move || {
+        println!("Runnable is running.");
+        Ok(())
+    });
     let _ = dbg!(func);
     // System::exit(0).unwrap();
 }
diff --git a/utils/src/lib.rs b/utils/src/lib.rs
index 5613ae4..fef20ed 100644
--- a/utils/src/lib.rs
+++ b/utils/src/lib.rs
@@ -350,6 +350,29 @@ pub fn android_context<'a>() -> JObject<'a> {
     unsafe { JObject::from_raw(ctx.context().cast()) }
 }
 
+
+/**
+加载一个java类。
+*/
+pub fn load_class<'a>(class_name: &str) -> Result<JClass<'a>> {
+    let mut env = vm_attach()?;
+    let activity = android_context();
+    let class_loader = env.call_method(
+        activity,
+        "getClassLoader",
+        "()Ljava/lang/ClassLoader;",
+        &[],
+    )?;
+    let cls_name = env.new_string(class_name)?;
+    let loaded_class = env.call_method(
+        class_loader.l()?,
+        "loadClass",
+        "(Ljava/lang/String;)Ljava/lang/Class;",
+        &[(&cls_name).into()],
+    )?;
+    Ok(loaded_class.l()?.into())
+}
+
 /// 创建一个java动态代理，用于在rust层实现java接口的方法。
 ///
 /// # Arguments