provide basic functionality that is used by almost all
applications. Other packages with names that begin with
supplemental APIs for specific features.
|java.lang Provides classes that are fundamental to the design of the Java programming language such as String, Math, and basic runtime support for threads and processes.||J2SE
J2SDK 1.4, and
|java.lang.annotation Provides library support for the Java programming language annotation facility.||New in J2SE 5.0|
|java.lang.instrument Provides services that allow Java programming language agents to instrument programs running on the JVM.||Java SE
|java.lang.management Provides the management interface for monitoring and management of the JVM as well as the operating system on which the JVM is running.||Java SE 6|
|java.lang.ref Provides reference-object classes, which support a limited degree of interaction with the garbage collector.||New in J2SDK 1.3||No additional information|
|java.lang.reflect Provides classes and interfaces for obtaining reflective information about classes and objects.||Java
J2SE 5.0, and
|java.util Provides the collections framework, formatted printing and scanning, array manipulation utilities, event model, date and time facilities, internationalization, and miscellaneous utility classes.||Java SE
J2SE 5.0, and
java.util.concurrent.locks Provides utility classes used in concurrent programming, including support for atomic updates of single variables and a locking framework which supplements language-level synchronization.
|New in J2SE 5.0|
java.util.zip Provides classes for reading and writing the standard ZIP and GZIP file formats as well as the JAR (Java ARchive) file format, which is based on the standard ZIP file format with an optional manifest file.
|Java SE 6
|java.util.logging Provides support to maintain and service software at customer sites.||J2SE 5.0
|java.util.regex Provides classes for matching character sequences against patterns specified by regular expressions.||New in J2SDK 1.4|
|java.util.prefs Provides classes to store and retrieve user and system preference and configuration data.||J2SDK 1.4|
|java.util.spi Service provider classes for the java.util package.||New in Java SE 6||No additional information|