hotspot source code - class file parse

Java 的版本号定义如下：

// Used for two backward compatibility reasons:
// - to check for new additions to the class file format in JDK1.5
// - to check for bug fixes in the format checker in JDK1.5
#define JAVA_1_5_VERSION                  49

// Used for backward compatibility reasons:
// - to check for javac bug fixes that happened after 1.5
// - also used as the max version when running in jdk6
#define JAVA_6_VERSION                    50

// Used for backward compatibility reasons:
// - to check NameAndType_info signatures more aggressively
#define JAVA_7_VERSION                    51

// Extension method support.
#define JAVA_8_VERSION                    52

Java7 常量池中新增加了3个常量类型，如InvokeDynamic，MethodHandle和MethodType，Java7 发布时 JVM 中新增加了一个指令invokedynamic，在常量池解析时就会碰到与这个指令直接相关的新增加的3个常量类型和新增加的属性BootstrapMethods：

void ClassFileParser::parse_constant_pool_entries(int length, TRAPS) {
  // Use a local copy of ClassFileStream. It helps the C++ compiler to optimize
  // this function (_current can be allocated in a register, with scalar
  // replacement of aggregates). The _current pointer is copied back to
  // stream() when this function returns. DON'T call another method within
  // this method that uses stream().
  ClassFileStream* cfs0 = stream();
  ClassFileStream cfs1 = *cfs0;
  ClassFileStream* cfs = &cfs1;
#ifdef ASSERT
  assert(cfs->allocated_on_stack(),"should be local");
  u1* old_current = cfs0->current();
#endif
  Handle class_loader(THREAD, _loader_data->class_loader());

  // Used for batching symbol allocations.
  const char* names[SymbolTable::symbol_alloc_batch_size];
  int lengths[SymbolTable::symbol_alloc_batch_size];
  int indices[SymbolTable::symbol_alloc_batch_size];
  unsigned int hashValues[SymbolTable::symbol_alloc_batch_size];
  int names_count = 0;

  // parsing  Index 0 is unused
  for (int index = 1; index < length; index++) {
    // Each of the following case guarantees one more byte in the stream
    // for the following tag or the access_flags following constant pool,
    // so we don't need bounds-check for reading tag.
    u1 tag = cfs->get_u1_fast();
    switch (tag) {
      case JVM_CONSTANT_Class :
        {
          cfs->guarantee_more(3, CHECK);  // name_index, tag/access_flags
          u2 name_index = cfs->get_u2_fast();
          _cp->klass_index_at_put(index, name_index);
        }
        break;
      case JVM_CONSTANT_Fieldref :
        {
          cfs->guarantee_more(5, CHECK);  // class_index, name_and_type_index, tag/access_flags
          u2 class_index = cfs->get_u2_fast();
          u2 name_and_type_index = cfs->get_u2_fast();
          _cp->field_at_put(index, class_index, name_and_type_index);
        }
        break;
      case JVM_CONSTANT_Methodref :
        {
          cfs->guarantee_more(5, CHECK);  // class_index, name_and_type_index, tag/access_flags
          u2 class_index = cfs->get_u2_fast();
          u2 name_and_type_index = cfs->get_u2_fast();
          _cp->method_at_put(index, class_index, name_and_type_index);
        }
        break;
      case JVM_CONSTANT_InterfaceMethodref :
        {
          cfs->guarantee_more(5, CHECK);  // class_index, name_and_type_index, tag/access_flags
          u2 class_index = cfs->get_u2_fast();
          u2 name_and_type_index = cfs->get_u2_fast();
          _cp->interface_method_at_put(index, class_index, name_and_type_index);
        }
        break;
      case JVM_CONSTANT_String :
        {
          cfs->guarantee_more(3, CHECK);  // string_index, tag/access_flags
          u2 string_index = cfs->get_u2_fast();
          _cp->string_index_at_put(index, string_index);
        }
        break;
      case JVM_CONSTANT_MethodHandle :
      case JVM_CONSTANT_MethodType :
        if (_major_version < Verifier::INVOKEDYNAMIC_MAJOR_VERSION) {
          classfile_parse_error(
            "Class file version does not support constant tag %u in class file %s",
            tag, CHECK);
        }
        if (!EnableInvokeDynamic) {
          classfile_parse_error(
            "This JVM does not support constant tag %u in class file %s",
            tag, CHECK);
        }
        if (tag == JVM_CONSTANT_MethodHandle) {
          cfs->guarantee_more(4, CHECK);  // ref_kind, method_index, tag/access_flags
          u1 ref_kind = cfs->get_u1_fast();
          u2 method_index = cfs->get_u2_fast();
          _cp->method_handle_index_at_put(index, ref_kind, method_index);
        } else if (tag == JVM_CONSTANT_MethodType) {
          cfs->guarantee_more(3, CHECK);  // signature_index, tag/access_flags
          u2 signature_index = cfs->get_u2_fast();
          _cp->method_type_index_at_put(index, signature_index);
        } else {
          ShouldNotReachHere();
        }
        break;
      case JVM_CONSTANT_InvokeDynamic :
        {
          if (_major_version < Verifier::INVOKEDYNAMIC_MAJOR_VERSION) {
            classfile_parse_error(
              "Class file version does not support constant tag %u in class file %s",
              tag, CHECK);
          }
          if (!EnableInvokeDynamic) {
            classfile_parse_error(
              "This JVM does not support constant tag %u in class file %s",
              tag, CHECK);
          }
          cfs->guarantee_more(5, CHECK);  // bsm_index, nt, tag/access_flags
          u2 bootstrap_specifier_index = cfs->get_u2_fast();
          u2 name_and_type_index = cfs->get_u2_fast();
          if (_max_bootstrap_specifier_index < (int) bootstrap_specifier_index)
            _max_bootstrap_specifier_index = (int) bootstrap_specifier_index;  // collect for later
          _cp->invoke_dynamic_at_put(index, bootstrap_specifier_index, name_and_type_index);
        }
        break;
      case JVM_CONSTANT_Integer :
        {
          cfs->guarantee_more(5, CHECK);  // bytes, tag/access_flags
          u4 bytes = cfs->get_u4_fast();
          _cp->int_at_put(index, (jint) bytes);
        }
        break;
      case JVM_CONSTANT_Float :
        {
          cfs->guarantee_more(5, CHECK);  // bytes, tag/access_flags
          u4 bytes = cfs->get_u4_fast();
          _cp->float_at_put(index, *(jfloat*)&bytes);
        }
        break;
      case JVM_CONSTANT_Long :
        // A mangled type might cause you to overrun allocated memory
        guarantee_property(index+1 < length,
                           "Invalid constant pool entry %u in class file %s",
                           index, CHECK);
        {
          cfs->guarantee_more(9, CHECK);  // bytes, tag/access_flags
          u8 bytes = cfs->get_u8_fast();
          _cp->long_at_put(index, bytes);
        }
        index++;   // Skip entry following eigth-byte constant, see JVM book p. 98
        break;
      case JVM_CONSTANT_Double :
        // A mangled type might cause you to overrun allocated memory
        guarantee_property(index+1 < length,
                           "Invalid constant pool entry %u in class file %s",
                           index, CHECK);
        {
          cfs->guarantee_more(9, CHECK);  // bytes, tag/access_flags
          u8 bytes = cfs->get_u8_fast();
          _cp->double_at_put(index, *(jdouble*)&bytes);
        }
        index++;   // Skip entry following eigth-byte constant, see JVM book p. 98
        break;
      case JVM_CONSTANT_NameAndType :
        {
          cfs->guarantee_more(5, CHECK);  // name_index, signature_index, tag/access_flags
          u2 name_index = cfs->get_u2_fast();
          u2 signature_index = cfs->get_u2_fast();
          _cp->name_and_type_at_put(index, name_index, signature_index);
        }
        break;
      case JVM_CONSTANT_Utf8 :
        {
          cfs->guarantee_more(2, CHECK);  // utf8_length
          u2  utf8_length = cfs->get_u2_fast();
          u1* utf8_buffer = cfs->get_u1_buffer();
          assert(utf8_buffer != NULL, "null utf8 buffer");
          // Got utf8 string, guarantee utf8_length+1 bytes, set stream position forward.
          cfs->guarantee_more(utf8_length+1, CHECK);  // utf8 string, tag/access_flags
          cfs->skip_u1_fast(utf8_length);

          // Before storing the symbol, make sure it's legal
          if (_need_verify) {
            verify_legal_utf8((unsigned char*)utf8_buffer, utf8_length, CHECK);
          }

          if (EnableInvokeDynamic && has_cp_patch_at(index)) {
            Handle patch = clear_cp_patch_at(index);
            guarantee_property(java_lang_String::is_instance(patch()),
                               "Illegal utf8 patch at %d in class file %s",
                               index, CHECK);
            char* str = java_lang_String::as_utf8_string(patch());
            // (could use java_lang_String::as_symbol instead, but might as well batch them)
            utf8_buffer = (u1*) str;
            utf8_length = (u2) strlen(str);
          }

          unsigned int hash;
          Symbol* result = SymbolTable::lookup_only((char*)utf8_buffer, utf8_length, hash);
          if (result == NULL) {
            names[names_count] = (char*)utf8_buffer;
            lengths[names_count] = utf8_length;
            indices[names_count] = index;
            hashValues[names_count++] = hash;
            if (names_count == SymbolTable::symbol_alloc_batch_size) {
              SymbolTable::new_symbols(_loader_data, _cp, names_count, names, lengths, indices, hashValues, CHECK);
              names_count = 0;
            }
          } else {
            _cp->symbol_at_put(index, result);
          }
        }
        break;
      default:
        classfile_parse_error(
          "Unknown constant tag %u in class file %s", tag, CHECK);
        break;
    }
  }

  // Allocate the remaining symbols
  if (names_count > 0) {
    SymbolTable::new_symbols(_loader_data, _cp, names_count, names, lengths, indices, hashValues, CHECK);
  }

  // Copy _current pointer of local copy back to stream().
#ifdef ASSERT
  assert(cfs0->current() == old_current, "non-exclusive use of stream()");
#endif
  cfs0->set_current(cfs1.current());
}

第2807行关于BootstrapMethods属性相关的解析：

void ClassFileParser::parse_classfile_bootstrap_methods_attribute(u4 attribute_byte_length, TRAPS) {
  ClassFileStream* cfs = stream();
  u1* current_start = cfs->current();

  guarantee_property(attribute_byte_length >= sizeof(u2),
                     "Invalid BootstrapMethods attribute length %u in class file %s",
                     attribute_byte_length,
                     CHECK);

  cfs->guarantee_more(attribute_byte_length, CHECK);

  int attribute_array_length = cfs->get_u2_fast();

  guarantee_property(_max_bootstrap_specifier_index < attribute_array_length,
                     "Short length on BootstrapMethods in class file %s",
                     CHECK);

  // The attribute contains a counted array of counted tuples of shorts,
  // represending bootstrap specifiers:
  //    length*{bootstrap_method_index, argument_count*{argument_index}}
  int operand_count = (attribute_byte_length - sizeof(u2)) / sizeof(u2);
  // operand_count = number of shorts in attr, except for leading length

  // The attribute is copied into a short[] array.
  // The array begins with a series of short[2] pairs, one for each tuple.
  int index_size = (attribute_array_length * 2);

  Array<u2>* operands = MetadataFactory::new_array<u2>(_loader_data, index_size + operand_count, CHECK);

  // Eagerly assign operands so they will be deallocated with the constant
  // pool if there is an error.
  _cp->set_operands(operands);

  int operand_fill_index = index_size;
  int cp_size = _cp->length();

  for (int n = 0; n < attribute_array_length; n++) {
    // Store a 32-bit offset into the header of the operand array.
    ConstantPool::operand_offset_at_put(operands, n, operand_fill_index);

    // Read a bootstrap specifier.
    cfs->guarantee_more(sizeof(u2) * 2, CHECK);  // bsm, argc
    u2 bootstrap_method_index = cfs->get_u2_fast();
    u2 argument_count = cfs->get_u2_fast();
    check_property(
      valid_cp_range(bootstrap_method_index, cp_size) &&
      _cp->tag_at(bootstrap_method_index).is_method_handle(),
      "bootstrap_method_index %u has bad constant type in class file %s",
      bootstrap_method_index,
      CHECK);

    guarantee_property((operand_fill_index + 1 + argument_count) < operands->length(),
      "Invalid BootstrapMethods num_bootstrap_methods or num_bootstrap_arguments value in class file %s",
      CHECK);

    operands->at_put(operand_fill_index++, bootstrap_method_index);
    operands->at_put(operand_fill_index++, argument_count);

    cfs->guarantee_more(sizeof(u2) * argument_count, CHECK);  // argv[argc]
    for (int j = 0; j < argument_count; j++) {
      u2 argument_index = cfs->get_u2_fast();
      check_property(
        valid_cp_range(argument_index, cp_size) &&
        _cp->tag_at(argument_index).is_loadable_constant(),
        "argument_index %u has bad constant type in class file %s",
        argument_index,
        CHECK);
      operands->at_put(operand_fill_index++, argument_index);
    }
  }

  assert(operand_fill_index == operands->length(), "exact fill");

  u1* current_end = cfs->current();
  guarantee_property(current_end == current_start + attribute_byte_length,
                     "Bad length on BootstrapMethods in class file %s",
                     CHECK);
}

vm/classfile/classFileParser.cpp第3721行，查看ClassFileParser::parseClassFile方法，源码如下：

instanceKlassHandle ClassFileParser::parseClassFile(Symbol* name,
                                                    ClassLoaderData* loader_data,
                                                    Handle protection_domain,
                                                    KlassHandle host_klass,
                                                    GrowableArray<Handle>* cp_patches,
                                                    TempNewSymbol& parsed_name,
                                                    bool verify,
                                                    TRAPS) {

  // When a retransformable agent is attached, JVMTI caches the
  // class bytes that existed before the first retransformation.
  // If RedefineClasses() was used before the retransformable
  // agent attached, then the cached class bytes may not be the
  // original class bytes.
  JvmtiCachedClassFileData *cached_class_file = NULL;
  Handle class_loader(THREAD, loader_data->class_loader());
  bool has_default_methods = false;
  bool declares_default_methods = false;
  ResourceMark rm(THREAD);

  ClassFileStream* cfs = stream();
  // Timing
  assert(THREAD->is_Java_thread(), "must be a JavaThread");
  JavaThread* jt = (JavaThread*) THREAD;

  PerfClassTraceTime ctimer(ClassLoader::perf_class_parse_time(),
                            ClassLoader::perf_class_parse_selftime(),
                            NULL,
                            jt->get_thread_stat()->perf_recursion_counts_addr(),
                            jt->get_thread_stat()->perf_timers_addr(),
                            PerfClassTraceTime::PARSE_CLASS);

  init_parsed_class_attributes(loader_data);

  if (JvmtiExport::should_post_class_file_load_hook()) {
    // Get the cached class file bytes (if any) from the class that
    // is being redefined or retransformed. We use jvmti_thread_state()
    // instead of JvmtiThreadState::state_for(jt) so we don't allocate
    // a JvmtiThreadState any earlier than necessary. This will help
    // avoid the bug described by 7126851.
    JvmtiThreadState *state = jt->jvmti_thread_state();
    if (state != NULL) {
      KlassHandle *h_class_being_redefined =
                     state->get_class_being_redefined();
      if (h_class_being_redefined != NULL) {
        instanceKlassHandle ikh_class_being_redefined =
          instanceKlassHandle(THREAD, (*h_class_being_redefined)());
        cached_class_file = ikh_class_being_redefined->get_cached_class_file();
      }
    }

    unsigned char* ptr = cfs->buffer();
    unsigned char* end_ptr = cfs->buffer() + cfs->length();

    JvmtiExport::post_class_file_load_hook(name, class_loader(), protection_domain,
                                           &ptr, &end_ptr, &cached_class_file);

    if (ptr != cfs->buffer()) {
      // JVMTI agent has modified class file data.
      // Set new class file stream using JVMTI agent modified
      // class file data.
      cfs = new ClassFileStream(ptr, end_ptr - ptr, cfs->source());
      set_stream(cfs);
    }
  }

  _host_klass = host_klass;
  _cp_patches = cp_patches;

  instanceKlassHandle nullHandle;

  // Figure out whether we can skip format checking (matching classic VM behavior)
  if (DumpSharedSpaces) {
    // verify == true means it's a 'remote' class (i.e., non-boot class)
    // Verification decision is based on BytecodeVerificationRemote flag
    // for those classes.
    _need_verify = (verify) ? BytecodeVerificationRemote :
                              BytecodeVerificationLocal;
  } else {
    _need_verify = Verifier::should_verify_for(class_loader(), verify);
  }

  // Set the verify flag in stream
  cfs->set_verify(_need_verify);

  // Save the class file name for easier error message printing.
  _class_name = (name != NULL) ? name : vmSymbols::unknown_class_name();

  cfs->guarantee_more(8, CHECK_(nullHandle));  // magic, major, minor
  // Magic value
  u4 magic = cfs->get_u4_fast();
  guarantee_property(magic == JAVA_CLASSFILE_MAGIC,
                     "Incompatible magic value %u in class file %s",
                     magic, CHECK_(nullHandle));

  // Version numbers
  u2 minor_version = cfs->get_u2_fast();
  u2 major_version = cfs->get_u2_fast();

  if (DumpSharedSpaces && major_version < JAVA_1_5_VERSION) {
    ResourceMark rm;
    warning("Pre JDK 1.5 class not supported by CDS: %u.%u %s",
            major_version,  minor_version, name->as_C_string());
    Exceptions::fthrow(
      THREAD_AND_LOCATION,
      vmSymbols::java_lang_UnsupportedClassVersionError(),
      "Unsupported major.minor version for dump time %u.%u",
      major_version,
      minor_version);
  }

  // Check version numbers - we check this even with verifier off
  if (!is_supported_version(major_version, minor_version)) {
    if (name == NULL) {
      Exceptions::fthrow(
        THREAD_AND_LOCATION,
        vmSymbols::java_lang_UnsupportedClassVersionError(),
        "Unsupported class file version %u.%u, "
        "this version of the Java Runtime only recognizes class file versions up to %u.%u",
        major_version,
        minor_version,
        JAVA_MAX_SUPPORTED_VERSION,
        JAVA_MAX_SUPPORTED_MINOR_VERSION);
    } else {
      ResourceMark rm(THREAD);
      Exceptions::fthrow(
        THREAD_AND_LOCATION,
        vmSymbols::java_lang_UnsupportedClassVersionError(),
        "%s has been compiled by a more recent version of the Java Runtime (class file version %u.%u), "
        "this version of the Java Runtime only recognizes class file versions up to %u.%u",
        name->as_C_string(),
        major_version,
        minor_version,
        JAVA_MAX_SUPPORTED_VERSION,
        JAVA_MAX_SUPPORTED_MINOR_VERSION);
    }
    return nullHandle;
  }

  _major_version = major_version;
  _minor_version = minor_version;


  // Check if verification needs to be relaxed for this class file
  // Do not restrict it to jdk1.0 or jdk1.1 to maintain backward compatibility (4982376)
  _relax_verify = Verifier::relax_verify_for(class_loader());

  // Constant pool
  constantPoolHandle cp = parse_constant_pool(CHECK_(nullHandle));

  int cp_size = cp->length();

  cfs->guarantee_more(8, CHECK_(nullHandle));  // flags, this_class, super_class, infs_len

  // Access flags
  AccessFlags access_flags;
  jint flags = cfs->get_u2_fast() & JVM_RECOGNIZED_CLASS_MODIFIERS;

  if ((flags & JVM_ACC_INTERFACE) && _major_version < JAVA_6_VERSION) {
    // Set abstract bit for old class files for backward compatibility
    flags |= JVM_ACC_ABSTRACT;
  }
  verify_legal_class_modifiers(flags, CHECK_(nullHandle));
  access_flags.set_flags(flags);

  // This class and superclass
  u2 this_class_index = cfs->get_u2_fast();
  check_property(
    valid_cp_range(this_class_index, cp_size) &&
      cp->tag_at(this_class_index).is_unresolved_klass(),
    "Invalid this class index %u in constant pool in class file %s",
    this_class_index, CHECK_(nullHandle));

  Symbol*  class_name  = cp->unresolved_klass_at(this_class_index);
  assert(class_name != NULL, "class_name can't be null");

  // It's important to set parsed_name *before* resolving the super class.
  // (it's used for cleanup by the caller if parsing fails)
  parsed_name = class_name;
  // parsed_name is returned and can be used if there's an error, so add to
  // its reference count.  Caller will decrement the refcount.
  parsed_name->increment_refcount();

  // Update _class_name which could be null previously to be class_name
  _class_name = class_name;

  // Don't need to check whether this class name is legal or not.
  // It has been checked when constant pool is parsed.
  // However, make sure it is not an array type.
  if (_need_verify) {
    guarantee_property(class_name->byte_at(0) != JVM_SIGNATURE_ARRAY,
                       "Bad class name in class file %s",
                       CHECK_(nullHandle));
  }

  Klass* preserve_this_klass;   // for storing result across HandleMark

  // release all handles when parsing is done
  { HandleMark hm(THREAD);

    // Checks if name in class file matches requested name
    if (name != NULL && class_name != name) {
      ResourceMark rm(THREAD);
      Exceptions::fthrow(
        THREAD_AND_LOCATION,
        vmSymbols::java_lang_NoClassDefFoundError(),
        "%s (wrong name: %s)",
        name->as_C_string(),
        class_name->as_C_string()
      );
      return nullHandle;
    }

    if (TraceClassLoadingPreorder) {
      tty->print("[Loading %s", (name != NULL) ? name->as_klass_external_name() : "NoName");
      if (cfs->source() != NULL) tty->print(" from %s", cfs->source());
      tty->print_cr("]");
    }
#if INCLUDE_CDS
    if (DumpLoadedClassList != NULL && cfs->source() != NULL && classlist_file->is_open()) {
      // Only dump the classes that can be stored into CDS archive
      if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
        if (name != NULL) {
          ResourceMark rm(THREAD);
          classlist_file->print_cr("%s", name->as_C_string());
          classlist_file->flush();
        }
      }
    }
#endif

    u2 super_class_index = cfs->get_u2_fast();
    instanceKlassHandle super_klass = parse_super_class(super_class_index,
                                                        CHECK_NULL);

    // Interfaces
    u2 itfs_len = cfs->get_u2_fast();
    Array<Klass*>* local_interfaces =
      parse_interfaces(itfs_len, protection_domain, _class_name,
                       &has_default_methods, CHECK_(nullHandle));

    u2 java_fields_count = 0;
    // Fields (offsets are filled in later)
    FieldAllocationCount fac;
    Array<u2>* fields = parse_fields(class_name,
                                     access_flags.is_interface(),
                                     &fac, &java_fields_count,
                                     CHECK_(nullHandle));
    // Methods
    bool has_final_method = false;
    AccessFlags promoted_flags;
    promoted_flags.set_flags(0);
    Array<Method*>* methods = parse_methods(access_flags.is_interface(),
                                            &promoted_flags,
                                            &has_final_method,
                                            &declares_default_methods,
                                            CHECK_(nullHandle));
    if (declares_default_methods) {
      has_default_methods = true;
    }

    // Additional attributes
    ClassAnnotationCollector parsed_annotations;
    parse_classfile_attributes(&parsed_annotations, CHECK_(nullHandle));

    // Finalize the Annotations metadata object,
    // now that all annotation arrays have been created.
    create_combined_annotations(CHECK_(nullHandle));

    // Make sure this is the end of class file stream
    guarantee_property(cfs->at_eos(), "Extra bytes at the end of class file %s", CHECK_(nullHandle));

    if (_class_name == vmSymbols::java_lang_Object()) {
      check_property(_local_interfaces == Universe::the_empty_klass_array(),
                     "java.lang.Object cannot implement an interface in class file %s",
                     CHECK_(nullHandle));
    }
    // We check super class after class file is parsed and format is checked
    if (super_class_index > 0 && super_klass.is_null()) {
      Symbol*  sk  = cp->klass_name_at(super_class_index);
      if (access_flags.is_interface()) {
        // Before attempting to resolve the superclass, check for class format
        // errors not checked yet.
        guarantee_property(sk == vmSymbols::java_lang_Object(),
                           "Interfaces must have java.lang.Object as superclass in class file %s",
                           CHECK_(nullHandle));
      }
      Klass* k = SystemDictionary::resolve_super_or_fail(class_name, sk,
                                                         class_loader,
                                                         protection_domain,
                                                         true,
                                                         CHECK_(nullHandle));

      KlassHandle kh (THREAD, k);
      super_klass = instanceKlassHandle(THREAD, kh());
    }
    if (super_klass.not_null()) {

      if (super_klass->has_default_methods()) {
        has_default_methods = true;
      }

      if (super_klass->is_interface()) {
        ResourceMark rm(THREAD);
        Exceptions::fthrow(
          THREAD_AND_LOCATION,
          vmSymbols::java_lang_IncompatibleClassChangeError(),
          "class %s has interface %s as super class",
          class_name->as_klass_external_name(),
          super_klass->external_name()
        );
        return nullHandle;
      }
      // Make sure super class is not final
      if (super_klass->is_final()) {
        THROW_MSG_(vmSymbols::java_lang_VerifyError(), "Cannot inherit from final class", nullHandle);
      }
    }

    // save super klass for error handling.
    _super_klass = super_klass;

    // Compute the transitive list of all unique interfaces implemented by this class
    _transitive_interfaces =
          compute_transitive_interfaces(super_klass, local_interfaces, CHECK_(nullHandle));

    // sort methods
    intArray* method_ordering = sort_methods(methods);

    // promote flags from parse_methods() to the klass' flags
    access_flags.add_promoted_flags(promoted_flags.as_int());

    // Size of Java vtable (in words)
    int vtable_size = 0;
    int itable_size = 0;
    int num_miranda_methods = 0;

    GrowableArray<Method*> all_mirandas(20);

    klassVtable::compute_vtable_size_and_num_mirandas(
        &vtable_size, &num_miranda_methods, &all_mirandas, super_klass(), methods,
        access_flags, class_loader, class_name, local_interfaces,
                                                      CHECK_(nullHandle));

    // Size of Java itable (in words)
    itable_size = access_flags.is_interface() ? 0 : klassItable::compute_itable_size(_transitive_interfaces);

    FieldLayoutInfo info;
    layout_fields(class_loader, &fac, &parsed_annotations, &info, CHECK_NULL);

    int total_oop_map_size2 =
          InstanceKlass::nonstatic_oop_map_size(info.total_oop_map_count);

    // Compute reference type
    ReferenceType rt;
    if (super_klass() == NULL) {
      rt = REF_NONE;
    } else {
      rt = super_klass->reference_type();
    }

    // We can now create the basic Klass* for this klass
    _klass = InstanceKlass::allocate_instance_klass(loader_data,
                                                    vtable_size,
                                                    itable_size,
                                                    info.static_field_size,
                                                    total_oop_map_size2,
                                                    rt,
                                                    access_flags,
                                                    name,
                                                    super_klass(),
                                                    !host_klass.is_null(),
                                                    CHECK_(nullHandle));
    instanceKlassHandle this_klass (THREAD, _klass);

    assert(this_klass->static_field_size() == info.static_field_size, "sanity");
    assert(this_klass->nonstatic_oop_map_count() == info.total_oop_map_count,
           "sanity");

    // Fill in information already parsed
    this_klass->set_should_verify_class(verify);
    jint lh = Klass::instance_layout_helper(info.instance_size, false);
    this_klass->set_layout_helper(lh);
    assert(this_klass->oop_is_instance(), "layout is correct");
    assert(this_klass->size_helper() == info.instance_size, "correct size_helper");
    // Not yet: supers are done below to support the new subtype-checking fields
    //this_klass->set_super(super_klass());
    this_klass->set_class_loader_data(loader_data);
    this_klass->set_nonstatic_field_size(info.nonstatic_field_size);
    this_klass->set_has_nonstatic_fields(info.has_nonstatic_fields);
    this_klass->set_static_oop_field_count(fac.count[STATIC_OOP]);

    apply_parsed_class_metadata(this_klass, java_fields_count, CHECK_NULL);

    if (has_final_method) {
      this_klass->set_has_final_method();
    }
    this_klass->copy_method_ordering(method_ordering, CHECK_NULL);
    // The InstanceKlass::_methods_jmethod_ids cache
    // is managed on the assumption that the initial cache
    // size is equal to the number of methods in the class. If
    // that changes, then InstanceKlass::idnum_can_increment()
    // has to be changed accordingly.
    this_klass->set_initial_method_idnum(methods->length());
    this_klass->set_name(cp->klass_name_at(this_class_index));
    if (is_anonymous())  // I am well known to myself
      cp->klass_at_put(this_class_index, this_klass()); // eagerly resolve

    this_klass->set_minor_version(minor_version);
    this_klass->set_major_version(major_version);
    this_klass->set_has_default_methods(has_default_methods);
    this_klass->set_declares_default_methods(declares_default_methods);

    if (!host_klass.is_null()) {
      assert (this_klass->is_anonymous(), "should be the same");
      this_klass->set_host_klass(host_klass());
    }

    // Set up Method*::intrinsic_id as soon as we know the names of methods.
    // (We used to do this lazily, but now we query it in Rewriter,
    // which is eagerly done for every method, so we might as well do it now,
    // when everything is fresh in memory.)
    if (Method::klass_id_for_intrinsics(this_klass()) != vmSymbols::NO_SID) {
      for (int j = 0; j < methods->length(); j++) {
        methods->at(j)->init_intrinsic_id();
      }
    }

    if (cached_class_file != NULL) {
      // JVMTI: we have an InstanceKlass now, tell it about the cached bytes
      this_klass->set_cached_class_file(cached_class_file);
    }

    // Fill in field values obtained by parse_classfile_attributes
    if (parsed_annotations.has_any_annotations())
      parsed_annotations.apply_to(this_klass);
    apply_parsed_class_attributes(this_klass);

    // Miranda methods
    if ((num_miranda_methods > 0) ||
        // if this class introduced new miranda methods or
        (super_klass.not_null() && (super_klass->has_miranda_methods()))
        // super class exists and this class inherited miranda methods
        ) {
      this_klass->set_has_miranda_methods(); // then set a flag
    }

    // Fill in information needed to compute superclasses.
    this_klass->initialize_supers(super_klass(), CHECK_(nullHandle));

    // Initialize itable offset tables
    klassItable::setup_itable_offset_table(this_klass);

    // Compute transitive closure of interfaces this class implements
    // Do final class setup
    fill_oop_maps(this_klass, info.nonstatic_oop_map_count, info.nonstatic_oop_offsets, info.nonstatic_oop_counts);

    // Fill in has_finalizer, has_vanilla_constructor, and layout_helper
    set_precomputed_flags(this_klass);

    // reinitialize modifiers, using the InnerClasses attribute
    int computed_modifiers = this_klass->compute_modifier_flags(CHECK_(nullHandle));
    this_klass->set_modifier_flags(computed_modifiers);

    // check if this class can access its super class
    check_super_class_access(this_klass, CHECK_(nullHandle));

    // check if this class can access its superinterfaces
    check_super_interface_access(this_klass, CHECK_(nullHandle));

    // check if this class overrides any final method
    check_final_method_override(this_klass, CHECK_(nullHandle));

    // check that if this class is an interface then it doesn't have static methods
    if (this_klass->is_interface()) {
      /* An interface in a JAVA 8 classfile can be static */
      if (_major_version < JAVA_8_VERSION) {
        check_illegal_static_method(this_klass, CHECK_(nullHandle));
      }
    }

    // Allocate mirror and initialize static fields
    java_lang_Class::create_mirror(this_klass, class_loader, protection_domain,
                                   CHECK_(nullHandle));

    // Generate any default methods - default methods are interface methods
    // that have a default implementation.  This is new with Lambda project.
    if (has_default_methods ) {
      DefaultMethods::generate_default_methods(
          this_klass(), &all_mirandas, CHECK_(nullHandle));
    }

    // Update the loader_data graph.
    record_defined_class_dependencies(this_klass, CHECK_NULL);

    ClassLoadingService::notify_class_loaded(InstanceKlass::cast(this_klass()),
                                             false /* not shared class */);

    if (TraceClassLoading) {
      ResourceMark rm;
      // print in a single call to reduce interleaving of output
      if (cfs->source() != NULL) {
        tty->print("[Loaded %s from %s]\n", this_klass->external_name(),
                   cfs->source());
      } else if (class_loader.is_null()) {
        Klass* caller =
            THREAD->is_Java_thread()
                ? ((JavaThread*)THREAD)->security_get_caller_class(1)
                : NULL;
        // caller can be NULL, for example, during a JVMTI VM_Init hook
        if (caller != NULL) {
          tty->print("[Loaded %s by instance of %s]\n",
                     this_klass->external_name(),
                     InstanceKlass::cast(caller)->external_name());
        } else {
          tty->print("[Loaded %s]\n", this_klass->external_name());
        }
      } else {
        tty->print("[Loaded %s from %s]\n", this_klass->external_name(),
                   InstanceKlass::cast(class_loader->klass())->external_name());
      }
    }

    if (TraceClassResolution) {
      ResourceMark rm;
      // print out the superclass.
      const char * from = this_klass()->external_name();
      if (this_klass->java_super() != NULL) {
        tty->print("RESOLVE %s %s (super)\n", from, InstanceKlass::cast(this_klass->java_super())->external_name());
      }
      // print out each of the interface classes referred to by this class.
      Array<Klass*>* local_interfaces = this_klass->local_interfaces();
      if (local_interfaces != NULL) {
        int length = local_interfaces->length();
        for (int i = 0; i < length; i++) {
          Klass* k = local_interfaces->at(i);
          InstanceKlass* to_class = InstanceKlass::cast(k);
          const char * to = to_class->external_name();
          tty->print("RESOLVE %s %s (interface)\n", from, to);
        }
      }
    }

    // preserve result across HandleMark
    preserve_this_klass = this_klass();
  }

  // Create new handle outside HandleMark (might be needed for
  // Extended Class Redefinition)
  instanceKlassHandle this_klass (THREAD, preserve_this_klass);
  debug_only(this_klass->verify();)

  // Clear class if no error has occurred so destructor doesn't deallocate it
  _klass = NULL;
  return this_klass;
}

References

1. vm/classfile/classFileParser.cpp