# Module java.base

Defines the foundational APIs of the Java SE Platform.

Providers:
  The JDK implementation of this module provides an implementation of the jrt file system provider to enumerate and read the class and resource files in a run-time image. The jrt file system can be created by calling `FileSystems.newFileSystem(URI.create("jrt:/"))`.
Tool Guides:
  java launcher, keytool

Since:
  9

- - ## Packages

    Exports
    Package | Description
    --- | ---
    java.io | Provides for system input and output through data streams, serialization and the file system.
    java.lang | Provides classes that are fundamental to the design of the Java programming language.
    java.lang.annotation | Provides library support for the Java programming language annotation facility.
    java.lang.constant | Classes and interfaces to represent nominal descriptors for run-time entities such as classes or method handles, and classfile entities such as constant pool entries or `invokedynamic` call sites.
    java.lang.invoke | The `java.lang.invoke` package provides low-level primitives for interacting with the Java Virtual Machine.
    java.lang.module | Classes to support module descriptors and creating configurations of modules by means of resolution and service binding.
    java.lang.ref | Provides reference-object classes, which support a limited degree of interaction with the garbage collector.
    java.lang.reflect | Provides classes and interfaces for obtaining reflective information about classes and objects.
    java.math | Provides classes for performing arbitrary-precision integer arithmetic (`BigInteger`) and arbitrary-precision decimal arithmetic (`BigDecimal`).
    java.net | Provides the classes for implementing networking applications.
    java.net.spi | Service-provider classes for the `java.net` package.
    java.nio | Defines buffers, which are containers for data, and provides an overview of the other NIO packages.
    java.nio.channels | Defines channels, which represent connections to entities that are capable of performing I/O operations, such as files and sockets; defines selectors, for multiplexed, non-blocking I/O operations.
    java.nio.channels.spi | Service-provider classes for the `java.nio.channels` package.
    java.nio.charset | Defines charsets, decoders, and encoders, for translating between bytes and Unicode characters.
    java.nio.charset.spi | Service-provider classes for the `java.nio.charset` package.
    java.nio.file | Defines interfaces and classes for the Java virtual machine to access files, file attributes, and file systems.
    java.nio.file.attribute | Interfaces and classes providing access to file and file system attributes.
    java.nio.file.spi | Service-provider classes for the `java.nio.file` package.
    java.security | Provides the classes and interfaces for the security framework.
    java.security.acl | The classes and interfaces in this package have been deprecated.
    java.security.cert | Provides classes and interfaces for parsing and managing certificates, certificate revocation lists (CRLs), and certification paths.
    java.security.interfaces | Provides interfaces for generating RSA (Rivest, Shamir and Adleman AsymmetricCipher algorithm) keys as defined in the RSA Laboratory Technical Note PKCS#1, and DSA (Digital Signature Algorithm) keys as defined in NIST's FIPS-186.
    java.security.spec | Provides classes and interfaces for key specifications and algorithm parameter specifications.
    java.text | Provides classes and interfaces for handling text, dates, numbers, and messages in a manner independent of natural languages.
    java.text.spi | Service provider classes for the classes in the java.text package.
    java.time | The main API for dates, times, instants, and durations.
    java.time.chrono | Generic API for calendar systems other than the default ISO.
    java.time.format | Provides classes to print and parse dates and times.
    java.time.temporal | Access to date and time using fields and units, and date time adjusters.
    java.time.zone | Support for time-zones and their rules.
    java.util | Contains the collections framework, some internationalization support classes, a service loader, properties, random number generation, string parsing and scanning classes, base64 encoding and decoding, a bit array, and several miscellaneous utility classes.
    java.util.concurrent | Utility classes commonly useful in concurrent programming.
    java.util.concurrent.atomic | A small toolkit of classes that support lock-free thread-safe programming on single variables.
    java.util.concurrent.locks | Interfaces and classes providing a framework for locking and waiting for conditions that is distinct from built-in synchronization and monitors.
    java.util.function | Functional interfaces provide target types for lambda expressions and method references.
    java.util.jar | Provides classes for reading and writing the JAR (Java ARchive) file format, which is based on the standard ZIP file format with an optional manifest file.
    java.util.regex | Classes for matching character sequences against patterns specified by regular expressions.
    java.util.spi | Service provider classes for the classes in the java.util package.
    java.util.stream | Classes to support functional-style operations on streams of elements, such as map-reduce transformations on collections.
    java.util.zip | Provides classes for reading and writing the standard ZIP and GZIP file formats.
    javax.crypto | Provides the classes and interfaces for cryptographic operations.
    javax.crypto.interfaces | Provides interfaces for Diffie-Hellman keys as defined in RSA Laboratories' PKCS #3.
    javax.crypto.spec | Provides classes and interfaces for key specifications and algorithm parameter specifications.
    javax.net | Provides classes for networking applications.
    javax.net.ssl | Provides classes for the secure socket package.
    javax.security.auth | This package provides a framework for authentication and authorization.
    javax.security.auth.callback | This package provides the classes necessary for services to interact with applications in order to retrieve information (authentication data including usernames or passwords, for example) or to display information (error and warning messages, for example).
    javax.security.auth.login | This package provides a pluggable authentication framework.
    javax.security.auth.spi | This package provides the interface to be used for implementing pluggable authentication modules.
    javax.security.auth.x500 | This package contains the classes that should be used to store X500 Principal and X500 Private Credentials in a Subject.
    javax.security.cert | Provides classes for public key certificates.

  - ## Services

    Provides
    Type | Description
    --- | ---
    FileSystemProvider |

    Uses
    Type | Description
    --- | ---
    AbstractChronology | An abstract implementation of a calendar system, used to organize and identify dates.
    AsynchronousChannelProvider | Service-provider class for asynchronous channels.
    BreakIteratorProvider | An abstract class for service providers that provide concrete implementations of the `BreakIterator` class.
    CalendarDataProvider | An abstract class for service providers that provide locale-dependent `Calendar` parameters.
    CalendarNameProvider | An abstract class for service providers that provide localized string representations (display names) of `Calendar` field values.
    CharsetProvider | Charset service-provider class.
    Chronology | A calendar system, used to organize and identify dates.
    CollatorProvider | An abstract class for service providers that provide concrete implementations of the `Collator` class.
    ContentHandlerFactory | This interface defines a factory for content handlers.
    CurrencyNameProvider | An abstract class for service providers that provide localized currency symbols and display names for the `Currency` class.
    DateFormatProvider | An abstract class for service providers that provide concrete implementations of the `DateFormat` class.
    DateFormatSymbolsProvider | An abstract class for service providers that provide instances of the `DateFormatSymbols` class.
    DecimalFormatSymbolsProvider | An abstract class for service providers that provide instances of the `DecimalFormatSymbols` class.
    FileSystemProvider | Service-provider class for file systems.
    FileTypeDetector | A file type detector for probing a file to guess its file type.
    LocaleNameProvider | An abstract class for service providers that provide localized names for the `Locale` class.
    LoginModule | Service-provider interface for authentication technology providers.
    NumberFormatProvider | An abstract class for service providers that provide concrete implementations of the `NumberFormat` class.
    Provider | This class represents a "provider" for the Java Security API, where a provider implements some or all parts of Java Security.
    ResourceBundleControlProvider | An interface for service providers that provide implementations of `ResourceBundle.Control`.
    ResourceBundleProvider | `ResourceBundleProvider` is a service provider interface for resource bundles.
    SelectorProvider | Service-provider class for selectors and selectable channels.
    System.LoggerFinder | The `LoggerFinder` service is responsible for creating, managing, and configuring loggers to the underlying framework it uses.
    TimeZoneNameProvider | An abstract class for service providers that provide localized time zone names for the `TimeZone` class.
    ToolProvider | An interface for command-line tools to provide a way to be invoked without necessarily starting a new VM.
    URLStreamHandlerProvider | URL stream handler service-provider class.
    ZoneRulesProvider | Provider of time-zone rules to the system.