java native newInstance0方法在jvm底层实现原理

蚰蜒螟2024-08-16 1:04

使用构造器反射对象实例

java 复制代码

private static native Object newInstance0(Constructor<?> c, Object[] args)
        throws InstantiationException,
               IllegalArgumentException,
               InvocationTargetException;

newInstance0底层实现逻辑

jvm源码

java 复制代码

JNIEXPORT jobject JNICALL Java_jdk_internal_reflect_NativeConstructorAccessorImpl_newInstance0
(JNIEnv *env, jclass unused, jobject c, jobjectArray args)
{
    return JVM_NewInstanceFromConstructor(env, c, args);
}

jvm.cpp实现这个方法JVM_NewInstanceFromConstructor

java 复制代码

JVM_ENTRY(jobject, JVM_NewInstanceFromConstructor(JNIEnv *env, jobject c, jobjectArray args0))
  JVMWrapper("JVM_NewInstanceFromConstructor");
  oop constructor_mirror = JNIHandles::resolve(c);
  objArrayHandle args(THREAD, objArrayOop(JNIHandles::resolve(args0)));
  oop result = Reflection::invoke_constructor(constructor_mirror, args, CHECK_NULL);
  jobject res = JNIHandles::make_local(env, result);
  if (JvmtiExport::should_post_vm_object_alloc()) {
    JvmtiExport::post_vm_object_alloc(JavaThread::current(), result);
  }
  return res;
JVM_END