Servlet API

Servlet API
Name	Servlet API
Developer	Apache Software Foundation, Oracle Corporation, Sun Microsystems
Initial release	1997
Latest release	4.0 (example)
Programming language	Java
Platform	Java Platform, Java EE, Jakarta EE
License	Apache License, Common Development and Distribution License

Servlet API The Servlet API provides a standardized Java Platform, Standard Edition-based interface for writing server-side components that process Hypertext Transfer Protocol requests and formulate responses, enabling interoperability across application servers, web containers, and Java Enterprise Edition implementations. It underpins frameworks and projects such as Apache Tomcat, Jetty, GlassFish, WildFly, and Spring Framework, shaping enterprise Jakarta EE web application development and integration with technologies like JavaServer Pages and JavaServer Faces.

Overview

The Servlet API specifies contracts between web components and web servers, defining how classes interact with containers such as Apache Tomcat, Eclipse Jetty, GlassFish, WildFly, and Resin while integrating with ecosystems like Spring Framework, Hibernate, Apache Struts, Grails, and Play Framework. It relates to standards from organizations including Oracle Corporation, Eclipse Foundation, Apache Software Foundation, Jakarta EE Working Group, and Java Community Process, and complements specifications like Java Servlet Specification, JavaServer Pages Specification, and Java Persistence API.

History and Development

The API originated from efforts at Sun Microsystems in the late 1990s alongside the emergence of JavaServer Pages and the growth of Enterprise JavaBeans patterns, with stewardship later involving Oracle Corporation and the Eclipse Foundation during the transition to Jakarta EE. Key milestones intersect with releases and projects such as Apache Tomcat 3 and 4, GlassFish launches, the formation of Java Community Process, the creation of Java EE and later Jakarta EE, and the move of specifications under Eclipse Foundation governance. Influential contributors and vendors include BEA Systems, IBM, Red Hat, Oracle, Apache Software Foundation, and community projects such as Spring Framework and Pivotal Software.

Architecture and Components

The Servlet API defines interactions among components like ServletContext, ServletConfig, HttpServletRequest, and HttpServletResponse which operate within a web container that implements lifecycle, threading, and resource management similar to containers within Apache Tomcat, Jetty, GlassFish, and WildFly. It interoperates with networking and protocol components including Hypertext Transfer Protocol, Secure Sockets Layer, Transport Layer Security, and server connectors such as those in Apache HTTP Server and NGINX. The architecture enables integration with application services like Java Naming and Directory Interface, Java Transaction API, Java Authentication and Authorization Service, Java Message Service, and persistence layers such as Hibernate and EclipseLink.

Core Interfaces and Classes

Core interfaces and classes specified by the API are implemented and extended by containers and frameworks such as Apache Tomcat, Eclipse Jetty, GlassFish, WildFly, Spring Framework, and Apache Struts. Notable elements in implementations and documentation often appear alongside projects like Maven Central, Gradle, Ant (software), Jenkins (software), Travis CI, and build tooling from Oracle Corporation. Vendors and contributors such as IBM, Red Hat, BEA Systems, Pivotal Software, F5 Networks, CA Technologies, and community projects such as Apache Geronimo provide reference implementations and compatibility test suites.

Lifecycle and Request Handling

Servlet lifecycle methods and request dispatch mechanisms are exercised in containers such as Apache Tomcat, Jetty, GlassFish, and WildFly, and integrated with frameworks like Spring MVC, Apache Struts, JSF, Grails, and Play Framework. Request models involve HTTP interactions related to Hypertext Transfer Protocol, HTTP/2, WebSocket Protocol, and TLS provided by infrastructure projects like OpenSSL, BoringSSL, NGINX, HAProxy, and Apache HTTP Server. Development workflows often involve tools and services such as Maven, Gradle, Jenkins, GitHub, GitLab, Bitbucket, and cloud platforms from Amazon Web Services, Google Cloud Platform, Microsoft Azure, and Heroku.

Security and Session Management

Security features and session management integrate with standards and products such as Java Authentication and Authorization Service, Transport Layer Security, OAuth 2.0, OpenID Connect, and identity providers like Okta, Auth0, Keycloak, Ping Identity, and Microsoft Azure Active Directory. Session handling interacts with clustering and persistence solutions from Hazelcast, Redis, Memcached, Apache Cassandra, Oracle Database, MySQL, PostgreSQL, and distributed platforms like Kubernetes and Docker. Auditing and compliance contexts involve entities and standards such as PCI DSS, GDPR, HIPAA, ISO/IEC 27001, and vendor tooling from Splunk, Elastic (company), Datadog, and New Relic.

Implementations and Compatibility

Major implementations include Apache Tomcat, Eclipse Jetty, GlassFish, WildFly, Resin, Oracle WebLogic Server, IBM WebSphere Application Server, and Apache Geronimo, while compatibility is tested via Technology Compatibility Kits produced by organizations like the Eclipse Foundation and overseen historically by the Java Community Process and vendors including Oracle Corporation, IBM, Red Hat, and SAP SE. Integration with cloud-native platforms and orchestration often references Kubernetes, Docker, OpenShift, Cloud Foundry, and enterprise offerings from Amazon Web Services, Microsoft Azure, and Google Cloud Platform.

Category:Java APIs