Explanation of the contents of each package in Java API

Java.applet provides classes and applets that are required to create applets to communicate with their applet contexts.
java.awt contains all the classes used to create the user interface and draw graphics images.
The Java.awt.color provides classes for color space.
Java.awt.datatransfer provides interfaces and classes that transfer data between applications and within applications.
Java.awt.dnd Drag and Drop are direct manipulation actions that are encountered in many graphical user interface systems and provide a mechanism to transfer information between two entities that are related to the display of element logic in the GUI.
Java.awt.event provides interfaces and classes for handling the various events that are fired by the AWT components.
Java.awt.font provides classes and interfaces related to fonts.
JAVA.AWT.GEOM provides Java classes for defining and performing operations on objects related to two-dimensional geometries.
JAVA.AWT.IM provides the classes and interfaces required for the input method framework.
JAVA.AWT.IM.SPI provides an interface that enables development of input methods that can be used in conjunction with the Java runtime environment.
Java.awt.image provides various classes for creating and modifying images.
Java.awt.image.renderable provides classes and interfaces for generating images that are not related to rendering.
Java.awt.print provides classes and interfaces for the common printing API.
Java.beans contains classes related to developing beans, which are components based on the javabeanstm architecture.
Java.beans.beancontext provides classes and interfaces related to the bean context.
The java.io provides system input and output through data flow, serialization, and file systems.
Java.lang provides the basic classes for programming using the Java programming language.
Java.lang.annotation provides library support for the Java programming language annotation facility.
Java.lang.instrument provides services that allow the Java programming language Agent to detect programs running on the JVM.
Java.lang.management provides a management interface for monitoring and managing the operating system on which Java virtual machines and Java virtual machines run.
JAVA.LANG.REF provides a reference object class that supports some degree of interaction with the garbage collector.
Java.lang.reflect provides classes and interfaces for reflection information about classes and objects.
The Java.math provides classes for performing arbitrary precision Integer Arithmetic (BigInteger) and arbitrary precision fractional arithmetic (BigDecimal).
Java.net provides classes for implementing network applications.
Java.nio defines a buffer as a data container and provides an overview of other NIO packages.
Java.nio.channels defines the various channels that represent connections to entities that can perform I/O operations, such as files and sockets, and selectors that are used for multiplexing, non-blocking I/O operations.
JAVA.NIO.CHANNELS.SPI the service provider class used for the Java.nio.channels package.
Java.nio.charset defines the charset, decoders, and encoders that are used to convert between byte and Unicode characters.
JAVA.NIO.CHARSET.SPI the service provider class for the Java.nio.charset package.
Java.rmi provides RMI packages.
Java.rmi.activation provides support for RMI object activation.
JAVA.RMI.DGC provides classes and interfaces for RMI distributed garbage collection.
Java.rmi.registry provides a class and two interfaces for the RMI registry.
The Java.rmi.server provides classes and interfaces that support server-side RMI.
Java.security provides classes and interfaces for the security framework.
Java.security.acl the classes and interfaces in this package have been superseded by the classes in the Java.security package.
Java.security.cert provides classes and interfaces for resolving and managing certificates, certificate revocation lists (CRLs), and certificate paths.
Java.security.interfaces provides an interface for generating RSA (Rivest, Shamir, and Adleman Asymmetriccipher defined in RSA Laboratory Technical Note pkcs#1 Algorithm) key, as well as the DSA (digital Signature algorithm) key defined in NIST's FIPS-186.
JAVA.SECURITY.SPEC provides classes and interfaces for key specification and algorithm parameter specification.
JAVA.SQL provides an API to access and process data stored in a data source (typically a relational database) using the JAVATM programming language.
Java.text provides classes and interfaces that work with text, dates, numbers, and messages in a way that is not related to natural language.
JAVA.TEXT.SPI the service provider class for the class in the Java.text package.
Java.util contains the collection framework, legacy collection classes, event models, date and time facilities, internationalization, and various utility classes (string tag generator, random number generator, and bit array).
Java.util.concurrent is a utility class that is commonly used in concurrent programming.
Java.util.concurrent.atomic-Class gadget package that supports thread-safe programming for unlocking on a single variable.
Java.util.concurrent.locks provides a framework interface and class for lock and wait conditions, unlike built-in synchronization and monitors.
Java.util.jar provides a class that reads and writes the JAR (Java ARchive) file format based on the standard ZIP file format with an optional manifest file.
Java.util.logging provides classes and interfaces for the JAVATM 2 platform core Logging tool.
Java.util.prefs This package allows applications to store and obtain user and system preferences and configuration data.
Java.util.regex class used to match a character sequence with a regular expression specifying a pattern.
JAVA.UTIL.SPI the service provider class for the class in the Java.util package.
The Java.util.zip provides classes for reading and writing standard zip and GZIP file formats.
Javax.accessibility defines the contract between the user interface components and the assistive technologies that provide access to those components.
Javax.crypto provides classes and interfaces for cryptographic operations.
Javax.crypto.interfaces provides a Diffie-hellman key interface based on the definition of the RSA Laboratories ' PKCS #3.
JAVAX.CRYPTO.SPEC provides classes and interfaces for key specifications and algorithm parameter specifications.
Javax.imageio The main package for the Java Image I/O API.
Javax.imageio.event a package for the Java image I/O API that handles synchronous notifications of events during the reading and writing of images.
Javax.imageio.metadata A package that handles the Java Image I/O API for reading and writing meta data.
Javax.imageio.plugins.bmp contains packages for common classes for use with built-in BMP plugins.
Javax.imageio.plugins.jpeg supports a class with a built-in JPEG plugin.
The JAVAX.IMAGEIO.SPI contains a plug-in interface for reader, writer, Transcoder, and Stream, and a Java Image I/O API package for a runtime registry.
Javax.imageio.stream a package from the Java Image I/O API to handle low-level I/O generated from files and streams.
Javax.management provides the core class of Java management Extensions.
Javax.management.loading provides classes that implement advanced dynamic loading.
Javax.management.modelmbean provides the definition of the Modelmbean class.
Javax.management.monitor provides the definition of the Monitor class.
Javax.management.openmbean provides open data types and open MBean descriptor classes.
Javax.management.relation provides the definition of the relation Service.
Javax.management.remote the interface used for remote access to the JMX MBean server.
The Javax.management.remote.rmi RMI Connector is a connector for use by the JMX remote API that uses RMI to transfer client requests to a remote MBean server.
The Javax.management.timer provides a definition of the timer mbean (timer Mbean).
Javax.naming provides classes and interfaces for accessing the naming service.
Javax.naming.directory extends the javax.naming package to provide access to directory services.
Javax.naming.event provides support for event notifications when accessing the naming and directory services.
JAVAX.NAMING.LDAP provides support for LDAPV3 extended operations and controls.
JAVAX.NAMING.SPI provides methods to dynamically insert support for access to naming and directory services through javax.naming and related packages.
The Javax.net provides classes for network applications.
The JAVAX.NET.SSL provides classes for Secure sockets packages.
Javax.print provides the main classes and interfaces for the JAVATM print Service API.
Javax.print.attribute provides classes and interfaces that describe the types of JAVATM print Service properties and how to categorize those properties.
Javax.print.attribute.standard package Javax.print.attribute.standard class that includes specific print properties.
The Javax.print.event package Javax.print.event contains the event class and listener interfaces.
Javax.rmi contains the user API for RMI-IIOP.
Javax.rmi.CORBA contains the portability API for RMI-IIOP.
JAVAX.RMI.SSL provides implementations of Rmiclientsocketfactory and rmiserversocketfactory through the Secure Sockets Layer (SSL) or Transport Layer Security (TLS) protocol.
Javax.security.auth This package provides a framework for validation and authorization.
Javax.security.auth.callback This package provides the classes necessary to interact with the application to retrieve information (for example, authentication data including user names and passwords) or display information (for example, error and warning messages).
Javax.security.auth.kerberos This package contains utility classes that are related to the Kerberos network authentication protocol.
Javax.security.auth.login This package provides an pluggable validation framework.
JAVAX.SECURITY.AUTH.SPI This package provides an interface for implementing pluggable validation modules.
Javax.security.auth.x500 This package contains classes that should be used to store X500 Principal and X500 Private crendentials in Subject.
Javax.security.cert provides classes for public key certificates.
The JAVAX.SECURITY.SASL contains classes and interfaces for supporting SASL.
The Javax.sound.midi provides interfaces and classes for I/O, serialization, and Composition for MIDI (musical Instrument Digital Interface) data.
JAVAX.SOUND.MIDI.SPI provides the interface that the service provider implements to provide new MIDI devices, MIDI file reader, and writer, or library reader.
The javax.sound.sampled provides interfaces and classes for capturing, processing, and replaying sampled audio data.
JAVAX.SOUND.SAMPLED.SPI provides a new audio device, sound file reader, and writer, or audio format converter, providing an abstract class for the service provider to which the subclass will be created.
Javax.sql provides APIs for server-side data source access and processing through the JAVATM programming language.
Javax.sql.rowset the standard interfaces and base classes implemented by the JDBC rowset.
Javax.sql.rowset.serial provides utility classes that allow serializable mappings between SQL types and Java programming language data types.
Javax.sql.rowset.spi the standard classes and interfaces that a third-party vendor must use in its implementation of the synchronization provider.
Javax.swing provides a set of "lightweight" (all Java-language) components that try to make these components work the same way on all platforms.
Javax.swing.border provides classes and interfaces that draw special borders around swing components.
Javax.swing.colorchooser contains classes and interfaces for use by JColorChooser components.
Javax.swing.event is used for events triggered by swing components.
Javax.swing.filechooser contains classes and interfaces used by JFileChooser components.
JAVAX.SWING.PLAF provides an interface and many abstract classes that swing uses to provide its own pluggable appearance functionality.
Javax.swing.plaf.basic provides user-interface objects built on a basic look.
Javax.swing.plaf.metal provides user interface objects built on the Java façade (formerly known as Metal), and the Java façade is the default appearance.
Javax.swing.plaf.multi provides user interface objects that combine two or more skins.
Javax.swing.plaf.synth Synth is the appearance of a replaceable skin (skinnable) in which all draws can be delegated.
The javax.swing.table provides classes and interfaces for handling javax.swing.JTable.
Javax.swing.text provides class HTMLEditorKit and support classes for creating HTML text editors.
Javax.swing.text.html provides class HTMLEditorKit and support classes for creating HTML text editors.
Javax.swing.text.html.parser provides the default HTML parser and support classes.
JAVAX.SWING.TEXT.RTF provides a class (Rtfeditorkit) for creating a text editor with rich text formatting (Rich-text-format).
Javax.swing.tree provides classes and interfaces for handling Javax.swing.JTree.
Javax.swing.undo allows developers to provide support for undo/redo in applications such as text editors.
The javax.transaction contains three exceptions thrown by the ORB mechanism during the solution group.
JAVAX.TRANSACTION.XA provides an API that defines the contract between the transaction manager and the resource manager, which allows the transaction manager to add or remove resource objects from the JTA transaction (provided by the Explorer driver).
Javax.xml defines core XML constants and functions according to the XML specification.
Javax.xml.bind provides a runtime binding framework for client applications that contain solution groups, marshalling, and validation capabilities.
Javax.xml.bind.annotation defines a comment that customizes Java program elements into XML Schema mappings.
Javax.xml.bind.annotation.adapters XMLAdapter and its specification subclasses allow any Java class to be used with JAXB.
Javax.xml.bind.attachment This package is implemented by a MIME-based package processor capable of interpreting and creating optimized binary data based on the MIME-formatted package format.
Javax.xml.bind.helpers is used only by the JAXB provider: to provide some default implementations of some Javax.xml.bind interfaces.
Javax.xml.bind.util A useful client utility class.
Javax.xml.crypto a generic class for XML encryption.
Javax.xml.crypto.dom the DOM-specific class of the Javax.xml.crypto package.
Javax.xml.crypto.dsig the class used to generate and validate XML digital signatures.
Javax.xml.crypto.dsig.dom Javax.xml.crypto.dsig packages are DOM-specific classes.
Javax.xml.crypto.dsig.keyinfo class used to parse and manipulate keyinfo elements and structures.
Javax.xml.crypto.dsig.spec the parameter class for XML digital signatures.
Javax.xml.datatype Xml/java Type mapping relationship.
Javax.xml.namespace XML namespace processing.
Javax.xml.parsers provides classes that allow processing of XML documents.
JAVAX.XML.SOAP provides APIs for creating and building SOAP messages.
Javax.xml.stream
Javax.xml.stream.events
Javax.xml.stream.util
Javax.xml.transform This package defines a generic API for processing conversion directives, and for performing transformations from source to result.
Javax.xml.transform.dom This package implements the DOM-specific conversion API.
Javax.xml.transform.sax This package implements the SAX2-specific conversion API.
Javax.xml.transform.stax provides Stax-specific conversion APIs.
Javax.xml.transform.stream This package implements a stream-and URI-specific conversion API.
Javax.xml.validation This package provides an API for XML document validation.
Javax.xml.ws This package contains the core JAX-ws API.
Javax.xml.ws.handler The package defines an API for message handlers.
Javax.xml.ws.handler.soap The package defines an API for SOAP message handlers.
Javax.xml.ws.http The package defines an API specific to the HTTP binding.
Javax.xml.ws.soap The package defines the API specific to the SOAP binding.
JAVAX.XML.WS.SPI The package defines the SPI for JAX-WS 2.0.
Javax.xml.xpath This package provides the Object-model neutral API for evaluating and accessing the compute environment for XPath expressions.
ORG.IETF.JGSS This package provides a framework that allows application developers to use a unified API to take advantage of a number of security services, such as authentication, data integrity, and data confidentiality, from a variety of underlying security mechanisms, such as Kerberos.
Org.omg.CORBA provides a mapping of the OMG CORBA API to the JAVATM programming language, including the ORB class, which, if implemented, can be used by programmers as a full-featured object request agent (object requests Broker,orb).
The Org.omg.CORBA_2_3 Corba_2_3 package defines the additions to the existing CORBA interfaces in Java[tm] standard Edition 6.
Org.omg.CORBA_2_3.portable provides various methods for input and output value types, and contains additional updates for the org/omg/corba/portable package.
The Org.omg.CORBA.DynAnyPackage provides exceptions (Invalidvalue, Invalid, Invalidseq, and Typemismatch) that are used with the DynAny interface.
Org.omg.CORBA.ORBPackage provides exception invalidname thrown by the Orb.resolve_initial_references method, and exceptions thrown by the dynamic any creation method in the ORB class Inconsistenttypecode.
Org.omg.CORBA.portable provides the portability layer, the Orb API collection that enables one vendor-generated code to run on another vendor's Orb.
Org.omg.CORBA.TypeCodePackage provides user-defined exceptions Badkind and Bounds, which are thrown by methods in the TypeCode class.
Org.omg.CosNaming provides a naming service for Java IDL.
Org.omg.CosNaming.NamingContextExtPackage This package contains the following classes that are used in ORG.OMG.COSNAMING.NAMINGCONTEXTEXT: Addresshelper Stringnamehelper Urlstringhelper invalidaddress Package specification for JAVA[TM] Platform, standard Edition 6 ORB comply with an explicit list of the supported parts of the official specification, see the Ficial specifications for CORBA Java[tm] SE 6.
Org.omg.CosNaming.NamingContextPackage This package contains the Exception class for the org.omg.CosNaming package.
Org.omg.Dynamic This package contains the Dynamic module specified in section 21.9 of the OMG Portable Interceptor Specification http://cgi.omg.org/cgi-bin/doc?ptc/2000-08-06.
Org.omg.DynamicAny provides classes and interfaces that enable you to traverse the data values associated with any at run time and extract the basic components of the data values.
Org.omg.DynamicAny.DynAnyFactoryPackage This package contains classes and exceptions in the Dynanyfactory interface of the Dynamicany module at the OMG the Common Object Request Bro Ker:architecture and specification http://cgi.omg.org/cgi-bin/doc?formal/99-10-07 are specified in section 9.2.2.
Org.omg.DynamicAny.DynAnyPackage This package contains classes and exceptions in the Dynanyfactory interface of the DynAny module at the OMG the Common Object Request broker:archite Cture and specification http://cgi.omg.org/cgi-bin/doc?formal/99-10-07 are specified in section 9.2.
Org.omg.IOP This package is included in the OMG document the Common Object Request broker:architecture and Specification Http://cgi.omg.org/cgi-bin/doc?f Ormal/99-10-07 13.6. The IOP module specified in the subsection.
Org.omg.IOP.CodecFactoryPackage This package contains the exception specified in the Iop::codefactory interface (as part of the Portable Interceptor specification).
Org.omg.IOP.CodecPackage This package is generated according to the Iop::codec IDL interface definition.
Org.omg.Messaging This package contains the Messaging module specified in the OMG Messaging Interceptor Specification http://cgi.omg.org/cgi-bin/doc?formal/99-10-07.
Org.omg.PortableInterceptor provides a mechanism for registering an orb hook (hook), through which the Orb service can intercept the normal flow of the execution orb.
Org.omg.PortableInterceptor.ORBInitInfoPackage This package contains the OMG Portable Interceptor Specification http://cgi.omg.org/cgi-bin/doc?ptc/ The exception and typedef in the Orbinitinfo local interface of the Portableinterceptor module specified in section 21.7.2 of 2000-08-06.
Org.omg.PortableServer provides classes and interfaces that are used to build the server side of portable applications across multiple vendor orbs.
Org.omg.PortableServer.CurrentPackage provides a variety of method implementations that enable access to the identity of the object that invokes the method.
Org.omg.PortableServer.POAManagerPackage encapsulates the processing state of the POA Association.
Org.omg.PortableServer.POAPackage allows programmers to construct object implementations that can be ported between different ORB products.
Org.omg.PortableServer.portable provides classes and interfaces that are used to build the server side of portable applications across multiple vendor orbs.
Org.omg.PortableServer.ServantLocatorPackage provides classes and interfaces for locating servant.
Org.omg.SendingContext provides support for grouping of value types.
The Org.omg.stub.java.rmi contains a rmi-iiop stub for the Remote type that appears in the Java.rmi package.
Org.w3c.dom provides an interface for the Document Object Model (DOM), which is the component API for the Java API for XML processing.
Org.w3c.dom.bootstrap
Org.w3c.dom.events
Org.w3c.dom.ls
Org.xml.sax This package provides the core sax API.
Org.xml.sax.ext This package contains interfaces for SAX2 facilities that are not necessarily supported by the sax driver.
Org.xml.sax.helpers This package contains the helper class, which includes support for booting sax-based applications.

Explanation of the contents of each package in Java API