==== 5.6.1 CONSTANT_Package ====

The **CONSTANT_Package_info** structure is used to represent a package: 

The items of the **CONSTANT_Package_info** structure are the following: 

**tag** 

The tag item has the value of **CONSTANT_Package** (13). 

**flags** 

The ****flags**** item is a mask of modifiers that apply to this package. The ****flags**** modifiers are shown in the following table. 

Flags 

Value 

**ACC_LIBRARY** 

**0x01** 

The ****ACC_LIBRARY**** flag has the value of one if this package does not define and declare any applets. In this case it is called a library package. Otherwise ****ACC_LIBRARY**** has the value of zero. 

If the package is not a library package this export file can only contain shareable interfaces.<SUP>[2]</SUP> A shareable interface is either the ****javacard.framework.Shareable**** interface or an interface that extends the ****javacard.framework.Shareable**** interface. 

All other flag values are reserved. Their values must be zero. 

**name_index** 

The value of the **name_index** item must be a valid index into the ****constant_pool**** table. The ****constant_pool**** entry at that index must be a **CONSTANT_Utf8_info** ([[5.6.4_CONSTANT_Utf8| Section 5.6.4, CONSTANT_Utf8]]) structure representing a valid Java package name. 

As in Java class files, ASCII periods (`.') that normally separate the identifiers in a package name are replaced by ASCII forward slashes (`/'). For example, the package name **javacard.framework** is represented in a **CONSTANT_Utf8_info** structure as **javacard/framework**. 

**minor_version, major_version** 

The **minor_version** and major_version items are the minor and major version numbers of this package. These values uniquely identify the particular implementation of this package and indicate the binary compatibility between packages. See [[4.5_Package Versions| Section 4.5, Package Versions]] for a description of assigning and using package version numbers. 

**aid_length** 

The value of the **aid_length** item gives the number of bytes in the aid array. Valid values are between 5 and 16, inclusive. 

**aid[]** 

The **aid** array contains the ISO AID of this package ([[4.2_AID-based Naming| Section 4.2, AID-based Naming]]).