fix: implement Class.is_array

Author: brianheineman

ristretto_vm/src/native_methods/java_lang_class.rs

@@ -23,6 +23,7 @@ pub(crate) fn register(registry: &mut MethodRegistry) {
         "(Ljava/lang/String;)Ljava/lang/Class;",
         get_primitive_class,
     );
+    registry.register(class_name, "isArray", "()Z", is_array);
     registry.register(class_name, "isPrimitive", "()Z", is_primitive);
     registry.register(class_name, "registerNatives", "()V", register_natives);
 }
@@ -68,6 +69,24 @@ fn get_primitive_class(
     })
 }
 
+#[expect(clippy::needless_pass_by_value)]
+fn is_array(
+    _call_stack: Arc<CallStack>,
+    mut arguments: Arguments,
+) -> Pin<Box<dyn Future<Output = Result<Option<Value>>>>> {
+    Box::pin(async move {
+        let Some(Reference::Object(object)) = arguments.pop_object()? else {
+            return Err(RuntimeError("isPrimitive: no arguments".to_string()));
+        };
+        let class = object.class();
+        if class.is_array() {
+            Ok(Some(Value::Int(1)))
+        } else {
+            Ok(Some(Value::Int(0)))
+        }
+    })
+}
+
 #[expect(clippy::needless_pass_by_value)]
 fn is_primitive(
     _call_stack: Arc<CallStack>,

ristretto_vm/src/vm.rs

@@ -1,5 +1,5 @@
 use crate::call_stack::CallStack;
-use crate::Error::UnsupportedClassFileVersion;
+use crate::Error::{RuntimeError, UnsupportedClassFileVersion};
 use crate::{Configuration, Result};
 use ristretto_classfile::{mutf8, Version};
 use ristretto_classloader::manifest::MAIN_CLASS;
@@ -144,22 +144,24 @@ impl VM {
                 .await?;
 
             // TODO: Implement System::initPhase2()
-            // let init_phase2_method = system_class.try_get_method("initPhase2", "(ZZ)I")?;
-            // let phase2_result = self.invoke(
-            //     &system_class,
-            //     &init_phase2_method,
-            //     vec![Value::Int(1), Value::Int(1)],
-            // )?;
-            // let Some(Value::Int(result)) = phase2_result else {
-            //     return Err(RuntimeError(format!(
-            //         "System::initPhase2() call failed: {phase2_result:?}"
-            //     )));
-            // };
-            // if result != 0 {
-            //     return Err(RuntimeError(format!(
-            //         "System::initPhase2() call failed: {result}"
-            //     )));
-            // }
+            let init_phase2_method = system_class.try_get_method("initPhase2", "(ZZ)I")?;
+            let phase2_result = self
+                .invoke(
+                    &system_class,
+                    &init_phase2_method,
+                    vec![Value::Int(1), Value::Int(1)],
+                )
+                .await?;
+            let Some(Value::Int(result)) = phase2_result else {
+                return Err(RuntimeError(format!(
+                    "System::initPhase2() call failed: {phase2_result:?}"
+                )));
+            };
+            if result != 0 {
+                return Err(RuntimeError(format!(
+                    "System::initPhase2() call failed: {result}"
+                )));
+            }
 
             // TODO: Implement System::initPhase3()
             // let init_phase3_method = system_class.try_get_method("initPhase3", "()V")?;