关于Java中的klass和class

class Main {
}

class Klass : public Metadata {
  friend class VMStructs;
 protected:
  // note: put frequently-used fields together at start of klass structure
  // for better cache behavior (may not make much of a difference but sure won't hurt)
  enum { _primary_super_limit = 8 };
  jint        _layout_helper;
  juint       _super_check_offset;
  Symbol*     _name;
  Klass*      _secondary_super_cache;
  // Array of all secondary supertypes
  Array<Klass*>* _secondary_supers;
  // Ordered list of all primary supertypes
  Klass*      _primary_supers[_primary_super_limit];
  // java/lang/Class instance mirroring this class
  oop       _java_mirror;
  // Superclass
  Klass*      _super;
  // First subclass (NULL if none); _subklass->next_sibling() is next one
  Klass*      _subklass;
  // Sibling link (or NULL); links all subklasses of a klass
  Klass*      _next_sibling;
  Klass*      _next_link;
  // The VM's representation of the ClassLoader used to load this class.
  // Provide access the corresponding instance java.lang.ClassLoader.
  ClassLoaderData* _class_loader_data;
  jint        _modifier_flags;  // Processed access flags, for use by Class.getModifiers.
  AccessFlags _access_flags;    // Access flags. The class/interface distinction is stored here.
  // Biased locking implementation and statistics
  // (the 64-bit chunk goes first, to avoid some fragmentation)
  jlong    _last_biased_lock_bulk_revocation_time;
  markOop  _prototype_header;   // Used when biased locking is both enabled and disabled for this type
  jint     _biased_lock_revocation_count;
  TRACE_DEFINE_KLASS_TRACE_ID;
  // Remembered sets support for the oops in the klasses.
  jbyte _modified_oops;             // Card Table Equivalent (YC/CMS support)
  jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
....
}

Main m = new Main();

 // java/lang/Class instance mirroring this class
  oop       _java_mirror;

Class m = Main.class;
Class m = Class.forName("Main");

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