Provides a standard implementation for several of the variants of the eval
method.

eval(Reader)eval(String)
eval(String, Bindings)eval(Reader, Bindings)
 are implemented using the abstract methods

eval(Reader,ScriptContext) or
eval(String, ScriptContext)

with a SimpleScriptContext.

A SimpleScriptContext is used as the default ScriptContext
of the AbstractScriptEngine..

A mapping of key/value pairs, all of whose keys are
Strings.

The optional interface implemented by ScriptEngines whose methods compile scripts
to a form that can be executed repeatedly without recompilation.

Extended by classes that store results of compilations.  State
might be stored in the form of Java classes, Java class files or scripting
language opcodes.  The script may be executed repeatedly
without reparsing.

Each CompiledScript is associated with a ScriptEngine -- A call to an  eval
method of the CompiledScript causes the execution of the script by the
ScriptEngine.  Changes in the state of the ScriptEngine caused by execution
of the CompiledScript  may visible during subsequent executions of scripts by the engine.

The optional interface implemented by ScriptEngines whose methods allow the invocation of
procedures in scripts that have previously been executed.

The interface whose implementing classes are used to connect Script Engines
with objects, such as scoped Bindings, in hosting applications.  Each scope is a set
of named attributes whose values can be set and retrieved using the
ScriptContext methods. ScriptContexts also expose Readers and Writers
that can be used by the ScriptEngines for input and output.

ScriptEngine is the fundamental interface whose methods must be
fully functional in every implementation of this specification.

These methods provide basic scripting functionality.  Applications written to this
simple interface are expected to work with minimal modifications in every implementation.
It includes methods that execute scripts, and ones that set and get values.

The values are key/value pairs of two types.  The first type of pairs consists of
those whose keys are reserved and defined in this specification or  by individual
implementations.  The values in the pairs with reserved keys have specified meanings.

The other type of pairs consists of those that create Java language Bindings, the values are
usually represented in scripts by the corresponding keys or by decorated forms of them.

ScriptEngineFactory is used to describe and instantiate
ScriptEngines.

Each class implementing ScriptEngine has a corresponding factory
that exposes metadata describing the engine class.
The ScriptEngineManager
uses the service provider mechanism described in the Jar File Specification to obtain
instances of all ScriptEngineFactories available in
the current ClassLoader.

The ScriptEngineManager implements a discovery and instantiation
mechanism for ScriptEngine classes and also maintains a
collection of key/value pairs storing state shared by all engines created
by the Manager. This class uses the service provider mechanism to enumerate all the
implementations of ScriptEngineFactory.
The ScriptEngineManager provides a method to return a list of all these factories
as well as utility methods which look up factories on the basis of language name, file extension
and mime type.

The Bindings of key/value pairs, referred to as the `Global Scope`  maintained
by the manager is available to all instances of ScriptEngine created
by the ScriptEngineManager.  The values in the Bindings are
generally exposed in all scripts.

The generic Exception class for the Scripting APIs.  Checked
exception types thrown by underlying scripting implementations must be wrapped in instances of
ScriptException.  The class has members to store line and column numbers and
filenames if this information is available.

A simple implementation of Bindings backed by
a HashMap or some other specified Map.

Simple implementation of ScriptContext.