The java.lang.* and java.util.* Packages

The java.lang and java.util packages provide basic functionality that is used by almost all applications. Other packages with names that begin with java.lang and java.util provide supplemental APIs for specific features.

Tutorials and Programmer's Guides

The Java Tutorial

API Enhancements

Package List

Package Enhancements More Information

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 5.0,
J2SDK 1.4, and
J2SDK 1.3

Package Version Identification

Location-Independent Access to Resources

Chained Exception Facility

java.lang.annotation
Provides library support for the Java programming language annotation facility.

New in J2SE 5.0

Using Annotations

java.lang.instrument
Provides services that allow Java programming language agents to instrument programs running on the JVM.

Java SE 6 and
J2SE 5.0

Instrumenting Applications

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

Monitoring and Management

java.lang.ref
Provides reference-object classes, which support a limited degree of interaction with the garbage collector.
New in J2SDK 1.3

java.lang.reflect
Provides classes and interfaces for obtaining reflective information about classes and objects.

Java SE 6,
J2SE 5.0, and
J2SDK 1.4

Reflection APIs

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 6,
J2SE 5.0, and
J2SDK 1.3

Collections Framework

java.util.concurrent
java.util.concurrent.atomic
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

Concurrency Utilities

java.util.jar
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 and
J2SDK 1.3

Java Archive (JAR) Files

java.util.logging
Provides support to maintain and service software at customer sites.

J2SE 5.0 and
J2SDK 1.4

Java Logging APIs

java.util.regex
Provides classes for matching character sequences against patterns specified by regular expressions.

New in J2SDK 1.4

Regular Expressions Tutorial

java.util.prefs
Provides classes to store and retrieve user and system preference and configuration data.

J2SDK 1.4

Preferences API

java.util.spi
Service provider classes for the java.util package.

New in Java SE 6

Package	Enhancements	More Information
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 5.0, J2SDK 1.4, and J2SDK 1.3	Package Version Identification Location-Independent Access to Resources Chained Exception Facility
java.lang.annotation Provides library support for the Java programming language annotation facility.	New in J2SE 5.0	Using Annotations
java.lang.instrument Provides services that allow Java programming language agents to instrument programs running on the JVM.	Java SE 6 and J2SE 5.0	Instrumenting Applications
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	Monitoring and Management
java.lang.ref Provides reference-object classes, which support a limited degree of interaction with the garbage collector.	New in J2SDK 1.3
java.lang.reflect Provides classes and interfaces for obtaining reflective information about classes and objects.	Java SE 6, J2SE 5.0, and J2SDK 1.4	Reflection APIs
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 6, J2SE 5.0, and J2SDK 1.3	Collections Framework
java.util.concurrent java.util.concurrent.atomic 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	Concurrency Utilities
java.util.jar 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 and J2SDK 1.3	Java Archive (JAR) Files
java.util.logging Provides support to maintain and service software at customer sites.	J2SE 5.0 and J2SDK 1.4	Java Logging APIs
java.util.regex Provides classes for matching character sequences against patterns specified by regular expressions.	New in J2SDK 1.4	Regular Expressions Tutorial
java.util.prefs Provides classes to store and retrieve user and system preference and configuration data.	J2SDK 1.4	Preferences API
java.util.spi Service provider classes for the java.util package.	New in Java SE 6

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