Package java.lang.constant
invokedynamic call sites.  These classes
 are suitable for use in bytecode reading and writing APIs, invokedynamic
 bootstraps, bytecode intrinsic APIs, and compile-time or link-time program
 analysis tools.
 Every API that reads and writes bytecode instructions needs to model the
 operands to these instructions and other classfile structures (such as entries
 in the bootstrap methods table or stack maps, which frequently reference
 entries in the classfile constant pool.) Such entries can denote values of
 fundamental types, such as strings or integers; parts of a program, such as
 classes or method handles; or values of arbitrary user-defined types.  The
 ConstantDesc hierarchy provides a representation of
 constant pool entries in nominal form that is convenient for APIs to model
 operands of bytecode instructions.
 
Nominal Descriptors
A ConstantDesc is a description of a constant
 value.  Such a description is the nominal form of the constant value;
 it is not the value itself, but rather a "recipe" for describing the value,
 storing the value in a constant pool entry, or reconstituting the value given
 a class loading context.  Every ConstantDesc
 knows how to resolve itself -- compute the value that it describes --
 via ConstantDesc.resolveConstantDesc.
 This allows an API which accepts ConstantDesc
 objects to evaluate them reflectively, provided that the classes and methods
 referenced in their nominal description are present and accessible.
 
The subtypes of ConstantDesc describe various kinds
 of constant values.  For each type of loadable constant pool entry defined in JVMS 4.4,
 there is a corresponding subtype of ConstantDesc:
 ClassDesc, MethodTypeDesc,
 DirectMethodHandleDesc, String,
 Integer, Long, Float,
 Double, and DynamicConstantDesc.  These classes
 provide type-specific accessor methods to extract the nominal information for
 that kind of constant.  When a bytecode-writing API encounters a ConstantDesc,
 it should examine it to see which of these types it is, cast it, extract
 its nominal information, and generate the corresponding entry to the constant pool.
 When a bytecode-reading API encounters a constant pool entry, it can
 convert it to the appropriate type of nominal descriptor.  For dynamic
 constants, bytecode-reading APIs may wish to use the factory
 DynamicConstantDesc.ofCanonical,
 which will inspect the bootstrap and, for well-known bootstraps, return
 a more specific subtype of DynamicConstantDesc, such as
 Enum.EnumDesc.
 
Another way to obtain the nominal description of a value is to ask the value
 itself.  A Constable is a type whose values
 can describe themselves in nominal form as a ConstantDesc.
 Fundamental types such as String and Class
 implement Constable, as can user-defined
 classes.  Entities that generate classfiles (such as compilers) can introspect
 over constable objects to obtain a more efficient way to represent their values
 in classfiles.
 
This package also includes DynamicCallSiteDesc,
 which represents a (non-loadable) Constant_InvokeDynamic_info constant
 pool entry.  It describes the bootstrap method, invocation name and type,
 and bootstrap arguments associated with an invokedynamic instruction.
 It is also suitable for describing invokedynamic call sites in bytecode
 reading and writing APIs.
 
Other members of this package are ModuleDesc
 and  PackageDesc. They represent module and package
 info structures, suitable for describing modules and their content in bytecode
 reading and writing APIs.
- See Java Virtual Machine Specification:
- 
4.4 The Constant Pool
- Since:
- 12
- 
ClassDescriptionA nominal descriptor for aClassconstant.Represents a type which is constable.A nominal descriptor for a loadable constant value, as defined in JVMS 4.4.Predefined values of nominal descriptor for common constants, including descriptors for primitive class types and other common platform types, and descriptors for method handles for standard bootstrap methods.A nominal descriptor for a directMethodHandle.Kinds of method handles that can be described with DirectMethodHandleDesc.A nominal descriptor for aninvokedynamiccall site.A nominal descriptor for a dynamic constant (one described in the constant pool withConstant_Dynamic_info.)A nominal descriptor for aMethodHandleconstant.A nominal descriptor for a MethodType constant.A nominal descriptor for aModuleconstant.A nominal descriptor for aPackageconstant.