Delegate null-parent class loading to bootstrap

Author: dlunch

java_runtime/src/classes/java/lang/class_loader.rs

@@ -183,7 +183,7 @@ impl ClassLoader {
             jvm.invoke_virtual(&parent, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;", (name.clone(),))
                 .await?
         } else {
-            None.into()
+            jvm.load_bootstrap_class(&name_str).await?.into()
         };
 
         if !class.is_null() {

java_runtime/tests/classes/java/lang/test_class.rs

@@ -246,9 +246,16 @@ async fn test_cldc_class_queries_and_new_instance() -> Result<()> {
 }
 
 #[tokio::test]
-async fn test_base_class_loader_find_class_throws() -> Result<()> {
+async fn test_base_class_loader_delegates_to_bootstrap_and_find_class_throws() -> Result<()> {
     let jvm = test_jvm().await?;
     let loader = jvm.new_class("java/lang/ClassLoader", "(Ljava/lang/ClassLoader;)V", (None,)).await?;
+
+    let name = JavaLangString::from_rust_string(&jvm, "java/util/Random").await?;
+    let class: ClassInstanceRef<Class> = jvm
+        .invoke_virtual(&loader, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;", (name,))
+        .await?;
+    assert!(!class.is_null());
+
     let name = JavaLangString::from_rust_string(&jvm, "missing.Type").await?;
 
     let result: Result<ClassInstanceRef<Class>> = jvm

jvm/src/jvm.rs

@@ -573,6 +573,13 @@ impl Jvm {
         self.resolve_class_internal(class_name, None).await
     }
 
+    pub async fn load_bootstrap_class(&self, class_name: &str) -> Result<Option<Box<dyn ClassInstance>>> {
+        let class = BootstrapClassLoaderWrapper::new(&*self.inner.bootstrap_class_loader)
+            .load_class(self, class_name)
+            .await?;
+        Ok(class.map(|class| class.java_class()))
+    }
+
     #[async_recursion::async_recursion]
     async fn resolve_class_internal(&self, class_name: &str, class_loader_wrapper: Option<&dyn ClassLoaderWrapper>) -> Result<Class> {
         tracing::trace!("Resolving class {class_name}");
@@ -722,11 +729,6 @@ impl Jvm {
     pub async fn exception(&self, r#type: &str, message: &str) -> JavaError {
         tracing::info!("throwing java exception: {} {message}", r#type);
 
-        if !self.has_class(r#type) {
-            self.resolve_class_internal(r#type, Some(&BootstrapClassLoaderWrapper::new(&*self.inner.bootstrap_class_loader)))
-                .await
-                .unwrap();
-        }
         let message_str = JavaLangString::from_rust_string(self, message).await.unwrap();
         let instance = self.new_class(r#type, "(Ljava/lang/String;)V", (message_str,)).await.unwrap();