==== 6.7.1 CONSTANT_Classref ====

The **CONSTANT_Classref_info** structure is used to represent a reference to a class or an interface. The class or interface may be defined in this package or in an imported package.  

The items in the **CONSTANT_Classref_info** structure are the following: 

**tag** 

The **tag** item has the value **CONSTANT_Classref** (1). 

**class_ref** 

The **class_ref** item represents a reference to a class or interface. If the class or interface is defined in this package the structure represents an internal_**class_ref** and the high bit of the structure is zero. If the class or interface is defined in another package the structure represents an external_**class_ref** and the high bit of the structure is one. 

**  internal_class_ref** 

The **internal_class_ref** structure represents a 16-bit offset into the **info** item of the Class Component ([[6.8_Class Component| Section 6.8, Class Component]]) to an interface_**info** or class_**info** structure. The interface_**info** or class_**info** structure must represent the referenced class or interface. 

The value of the **internal_class_ref** item must be between 0 and 32767, inclusive, making the high bit equal to zero. 

**  external_class_ref** 

The **external_class_ref** structure represents a reference to a class or interface defined in an imported package. The high bit of this structure is one. 

**     package_token** 

The **package_token** item represents a package token ([[4.3.7.1_Package| Section 4.3.7.1, Package]]) defined in the Import Component ([[6.6_Import Component| Section 6.6, Import Component]]) of this CAP file. The value of this token must be a valid index into the packages table item of the **import_component** structure. The package represented at that index must be the imported package. 

The value of the package token must be between 0 and 127, inclusive. 

The high bit of the **package_token** item is equal to one. 

**     class_token** 

**The class_token** item represents the token of the class or interface ([[4.3.7.2_Classes and Interfaces| Section 4.3.7.2, Classes and Interfaces]]) of the referenced class or interface. It has the value of the class token of the class as defined in the **Export** file of the imported package. 

**padding** 

The **padding** item has the value zero. It is present to make the size of a **CONSTANT_Classref_info** structure the same as all other constants in the **constant_pool[]** array.