Apache Tomcat

Last updated
Apache Tomcat
Original author(s) James Duncan Davidson
Developer(s) The Apache Software Foundation
Initial release1999;25 years ago (1999)
Stable release
10.1.19 [1]   OOjs UI icon edit-ltr-progressive.svg / 19 February 2024
Repository Tomcat Repository
Written in Java
Type Servlet container
HTTP web server
License Apache-2.0
Website tomcat.apache.org   OOjs UI icon edit-ltr-progressive.svg

Apache Tomcat (called "Tomcat" for short) is a free and open-source implementation of the Jakarta Servlet, Jakarta Expression Language, and WebSocket technologies. [2] It provides a "pure Java" HTTP web server environment in which Java code can also run. Thus it is a Java web application server, although not a full JEE application server.

Contents

Tomcat is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation, released under the Apache License 2.0 license.

Components

Tomcat 4.x was released with Catalina (a servlet container), Coyote (an HTTP connector) and Jasper (a JSP engine).

Catalina

Catalina is Tomcat's servlet container. Catalina implements Sun Microsystems' specifications for servlet and JavaServer Pages (JSP). In Tomcat, a Realm element represents a "database" of usernames, passwords, and roles (similar to Unix groups) assigned to those users. Different implementations of Realm allow Catalina to be integrated into environments where such authentication information is already being created and maintained, and then use that information to implement Container Managed Security as described in the Servlet Specification. [3]

Coyote

Coyote is a Connector component for Tomcat that supports the HTTP 1.1 and 2 protocol as a web server. This allows Catalina, nominally a Java Servlet or JSP container, to also act as a plain web server that serves local files as HTTP documents. [4] Coyote listens for incoming connections to the server on a specific TCP port and forwards the request to the Tomcat Engine to process the request and send back a response to the requesting client. Another Coyote Connector, Coyote JK, listens similarly but instead forwards its requests to another web server, such as Apache, using the JK Protocol. [5] This usually offers better performance.[ citation needed ]

Jasper

Jasper is Tomcat's JSP Engine. Jasper parses JSP files to compile them into Java code as servlets (that can be handled by Catalina). At runtime, Jasper detects changes to JSP files and recompiles them.

As of version 5, Tomcat uses Jasper 2, which is an implementation of the Sun Microsystems' JSP 2.0 specification. From Jasper to Jasper 2, important features were added:

Three new components were added with the release of Tomcat 7:

Cluster

This component has been added to manage large applications. It is used for load balancing that can be achieved through many techniques. Clustering support currently requires the JDK version 1.5 or higher.

High availability

A high-availability feature has been added to facilitate the scheduling of system upgrades (e.g. new releases, change requests) without affecting the live environment. This is done by dispatching live traffic requests to a temporary server on a different port while the main server is upgraded on the main port. It is very useful in handling user requests on high-traffic web applications. [6]

Features

Tomcat 8.x implements the Servlet 3.1 and JSP 2.3 Specifications. [7] Apache Tomcat 8.5.x is intended to replace 8.0.x and includes new features pulled forward from Tomcat 9.0.x. The minimum Java version and implemented specification versions remain unchanged. [8]

Tomcat 9.x implements the Servlet 4.0 and JSP 2.3 Specifications. [9]

Tomcat 10.0.x implements the Servlet 5.0 and JSP 3.0 Specifications. [9]

Tomcat 10.1.x implements the Servlet 6.0 and JSP 3.1 Specifications. [9]

History

Tomcat started off as a servlet reference implementation by James Duncan Davidson, a software architect at Sun Microsystems. He later helped make the project open-source and played a key role in its donation by Sun Microsystems to the Apache Software Foundation. [10] The Apache Ant software build automation tool was developed as a side-effect of the creation of Tomcat as an open source project.

Davidson had initially hoped that the project would become open-sourced and, since many open-source projects had O'Reilly books associated with them featuring an animal on the cover, he wanted to name the project after an animal. He came up with Tomcat since he reasoned the animal represented something that could fend for itself. Although the tomcat was already in use for another O'Reilly title, [11] his wish to see an animal cover eventually came true when O'Reilly published their Tomcat book with a snow leopard on the cover in 2003. [12]

Releases

Series [13] Declared stableDescriptionLatest releaseLatest release dateEnd of life [14]
Old version, no longer maintained: 2.01998Tomcat started off in November 1998 [15] as a servlet reference implementation by James Duncan Davidson, a software architect at Sun Microsystems.???
Old version, no longer maintained: 3.01999Initial release. Merger of donated Sun Java Web Server code and ASF and Implements Servlet 2.2, and JSP 1.1 specifications.3.3.22004-03-09?
Old version, no longer maintained: 4.12002-09-06 [16] First Apache Tomcat release to support the Servlet 2.3 and JSP 1.2 [17] specifications.4.1.402009-06-25?
Old version, no longer maintained: 5.02003-12-03Supports the Servlet 2.4, JSP 2.0, and EL 1.1 [17] specifications.5.0.302004-08-30?
Old version, no longer maintained: 5.5 [18] 2004-11-10 [19] Designed for J2SE 5.0. Inclusion of Eclipse JDT allows Tomcat to run without a full Java Development Kit being installed.5.5.362012-10-102012-09-30 [20]
Old version, no longer maintained: 6.02007-02-28 [21] Supports the Servlet 2.5, JSP 2.1, [17] and EL 2.1 specifications.6.0.532017-04-072016-12-31 [22]
Old version, no longer maintained: 7.02011-01-14 [23] Supports the Servlet 3.0, JSP 2.2, EL 2.2, and WebSocket [17] specifications.7.0.1092021-04-26 [24] 2021-03-31 [25]
Old version, no longer maintained: 8.02014-06-25 [26] Supports the Servlet 3.1, JSP 2.3, and EL 3.0 [17] specifications.8.0.532018-07-052018-06-30 [27]
Older version, yet still maintained: 8.52016-06-13Adds support for HTTP/2, OpenSSL for JSSE, TLS virtual hosting and JASPIC 1.1. Created from Tomcat 9, following delays to Java EE 8.8.5.952023-10-16 [28] 2024-03-31 [29]
Older version, yet still maintained: 9.02018-01-18Supports the Servlet 4.0 [17] specifications.9.0.852023-10-13 [30] TBA
Old version, no longer maintained: 10.02021-02-02Supports the Servlet 5.0, JSP 3.0, EL 4.0, WebSocket 2.0 and Authentication 2.0 [17] specifications.10.0.272022-10-10 [31] 2022-10-31 [32]
Current stable version:10.12022-09-26Supports the Jakarta Servlet 6.0, JSP 3.1, EL 5.0, WebSocket 2.1, and JASPIC 3.0 [17] specifications.10.1.182023-11-10 [33] TBA
Latest preview version of a future release: 11.0(alpha)Supports the Jakarta Servlet 6.1, JSP 4.0, and as-yet-to-be-determined versions of EL, WebSocket, and JASPIC [17] specifications.11.0.0-M162023-10-14 [34] TBA
Legend:
Old version
Older version, still maintained
Latest version
Latest preview version
Future release


Apache TomEE

Apache TomEE (pronounced "Tommy") is the Java Enterprise Edition of Apache Tomcat (Tomcat + Java EE = TomEE) that combines several Java enterprise projects including Apache OpenEJB, Apache OpenWebBeans, Apache OpenJPA, Apache MyFaces and others. [35] In October 2011, the project obtained certification by Oracle Corporation as a compatible implementation of the Java EE 6 Web Profile. [36] [37]

See also

Related software that is now obsolete or defunct:

Related Research Articles

Jakarta Enterprise Beans is one of several Java APIs for modular construction of enterprise software. EJB is a server-side software component that encapsulates business logic of an application. An EJB web container provides a runtime environment for web related software components, including computer security, Java servlet lifecycle management, transaction processing, and other web services. The EJB specification is a subset of the Java EE specification.

<span class="mw-page-title-main">Jakarta EE</span> Set of specifications extending Java SE

Jakarta EE, formerly Java Platform, Enterprise Edition and Java 2 Platform, Enterprise Edition (J2EE), is a set of specifications, extending Java SE with specifications for enterprise features such as distributed computing and web services. Jakarta EE applications are run on reference runtimes, which can be microservices or application servers, which handle transactions, security, scalability, concurrency and management of the components they are deploying.

Jakarta Server Pages is a collection of technologies that helps software developers create dynamically generated web pages based on HTML, XML, SOAP, or other document types. Released in 1999 by Sun Microsystems, JSP is similar to PHP and ASP, but uses the Java programming language.

<span class="mw-page-title-main">Jakarta Servlet</span> Jakarta EE programming language class

A Jakarta Servlet, formerly Java Servlet is a Java software component that extends the capabilities of a server. Although servlets can respond to many types of requests, they most commonly implement web containers for hosting web applications on web servers and thus qualify as a server-side servlet web API. Such web servlets are the Java counterpart to other dynamic web content technologies such as PHP and ASP.NET.

The Jakarta Project created and maintained open source software for the Java platform. It operated as an umbrella project under the auspices of the Apache Software Foundation, and all Jakarta products are released under the Apache License. As of December 21, 2011 the Jakarta project was retired because no subprojects were remaining.

An application server is a server that hosts applications or software that delivers a business application through a communication protocol. For a typical web application, the application server sits behind the web servers.

A web container is the component of a web server that interacts with Jakarta Servlets. A web container is responsible for managing the lifecycle of servlets, mapping a URL to a particular servlet and ensuring that the URL requester has the correct access-rights. A web container handles requests to servlets, Jakarta Server Pages (JSP) files, and other types of files that include server-side code. The Web container creates servlet instances, loads and unloads servlets, creates and manages request and response objects, and performs other servlet-management tasks. A web container implements the web component contract of the Jakarta EE architecture. This architecture specifies a runtime environment for additional web components, including security, concurrency, lifecycle management, transaction, deployment, and other services.

Java Management Extensions (JMX) is a Java technology that supplies tools for managing and monitoring applications, system objects, devices and service-oriented networks. Those resources are represented by objects called MBeans. In the API, classes can be dynamically loaded and instantiated. Managing and monitoring applications can be designed and developed using the Java Dynamic Management Kit.

<span class="mw-page-title-main">JSP model 2 architecture</span>

JSP Model 2 is a complex design pattern used in the design of Java Web applications which separates the display of content from the logic used to obtain and manipulate the content. Since Model 2 drives a separation between logic and display, it is usually associated with the model–view–controller (MVC) paradigm. While the exact form of the MVC "Model" was never specified by the Model 2 design, a number of publications recommend a formalized layer to contain MVC Model code. The Java BluePrints, for example, originally recommended using EJBs to encapsulate the MVC Model.

<span class="mw-page-title-main">JOnAS</span>

JOnAS is an open-source implementation of the Java EE application server specification, developed and hosted by the OW2 consortium, having been originally been created by Groupe Bull. JOnAS is released under the LGPL 2.1 open-source license.

<span class="mw-page-title-main">Apache Geronimo</span> Open-source web application server

Apache Geronimo is an open source application server developed by the Apache Software Foundation and distributed under the Apache license.

<span class="mw-page-title-main">Apache Axis</span> Web service framework

Apache Axis is an open-source, XML based Web service framework. It consists of a Java and a C++ implementation of the SOAP server, and various utilities and APIs for generating and deploying Web service applications. Using Apache Axis, developers can create interoperable, distributed computing applications. Axis development takes place under the auspices of the Apache Software Foundation.

mod_jk is an Apache module used to connect the Tomcat servlet container with web servers such as Apache, iPlanet, Sun ONE and even IIS using the Apache JServ Protocol. The mod_proxy_ajp module performs a similar function to this module, while being integrated into the mod_proxy framework.

Web server software allows computers to act as web servers. The first web servers supported only static files, such as HTML, but now they commonly allow embedding of server side applications.

<span class="mw-page-title-main">GlassFish</span> Application server project

GlassFish is an open-source Jakarta EE platform application server project started by Sun Microsystems, then sponsored by Oracle Corporation, and now living at the Eclipse Foundation and supported by OmniFish, Fujitsu and Payara. The supported version under Oracle was called Oracle GlassFish Server. GlassFish is free software and was initially dual-licensed under two free software licences: the Common Development and Distribution License (CDDL) and the GNU General Public License (GPL) with the Classpath exception. After having been transferred to Eclipse, GlassFish remained dual-licensed, but the CDDL license was replaced by the Eclipse Public License (EPL).

In software engineering, a WAR file is a file used to distribute a collection of JAR-files, JavaServer Pages, Java Servlets, Java classes, XML files, tag libraries, static web pages and other resources that together constitute a web application.

The Apache JServ Protocol (AJP) is a binary protocol that can proxy inbound requests from a web server through to an application server that sits behind the web server. AJP is a highly trusted protocol and should never be exposed to untrusted clients, which could use it to gain access to sensitive information or execute code on the application server.

The JBoss Enterprise Application Platform is a subscription-based/open-source Java EE-based application server runtime platform used for building, deploying, and hosting highly-transactional Java applications and services developed and maintained by Red Hat. The JBoss Enterprise Application Platform is part of Red Hat's Enterprise Middleware portfolio of software. Because it is Java-based, the JBoss application server operates across platforms; it is usable on any operating system that supports Java. JBoss Enterprise Application Platform was originally called JBoss and was developed by the eponymous company JBoss, acquired by Red Hat in 2006.

OpenEJB is an open-source, embeddable and lightweight Enterprise JavaBeans Container System and EJB Server, released under the Apache License 2.0. OpenEJB has been integrated with Java EE application servers such as Geronimo and WebObjects.

<span class="mw-page-title-main">Apache TomEE</span> Computer Software

Apache TomEE is the Java Enterprise Edition of Apache Tomcat that combines several Java enterprise projects including Apache OpenEJB, Apache OpenWebBeans, Apache OpenJPA, Apache MyFaces and others. In October 2011, the project obtained certification by Oracle Corporation as a compatible implementation of the Java EE 6 Web Profile.

References

  1. ↑ "Tomcat 10.1.19 (schultz)". 19 February 2024. Retrieved 20 February 2024.
  2. ↑ "How to install Apache Tomcat on Ubuntu Server 16.04". 21 March 2017. Retrieved 2019-10-04.
  3. ↑ "Apache Tomcat Configuration Reference - The Realm Component". Tomcat.apache.org. Retrieved 2013-11-01.
  4. ↑ The Coyote HTTP/1.1 Connector, Apache
  5. ↑ "Server Configuration Reference - The Coyote JK Connector". tomcat.apache.org. Retrieved 24 August 2018.
  6. ↑ King, Graham (December 20, 2004). "High availability Tomcat". JavaWorld . Retrieved 2020-07-21.
  7. ↑ "Apache Tomcat - Apache Tomcat 8 Software Downloads". tomcat.apache.org. Retrieved 24 August 2018.
  8. ↑ McClanahan, Craig R. "Apache Tomcat 8 (8.5.33) - Documentation Index". tomcat.apache.org. Retrieved 24 August 2018.
  9. 1 2 3 "Apache Tomcat Versions" . Retrieved 2022-08-26.
  10. ↑ Davidson, James Duncan (November 14, 2014). "What was the history of Tomcat inside Sun before it was open-sourced?". Quora . Retrieved 2018-07-25.
  11. ↑ Sinan Si Alhir (1998), UML in a Nutshell, O'Reilly Books, pp.  296, ISBN   978-1-56592-448-2
  12. ↑ Brittain, Jason; Darwin, Ian F. (28 November 2007), Tomcat: The Definitive Guide (1st ed.), O'Reilly Media, p.  320, ISBN   978-0596003180 , retrieved 2018-03-01
  13. ↑ Apache Tomcat Versions
  14. ↑ "Tomcat Versions - Apache Tomcat". cwiki.apache.org. The Apache Software Foundation . Retrieved 2020-07-20.
  15. ↑ "The Origin Story of Tomcat". TechNotif. 24 April 2015. Archived from the original on 30 June 2018. Retrieved 23 July 2017.
  16. ↑ "[ANNOUNCEMENT] Tomcat 4.1.10 Stable" . Retrieved 21 September 2015.
  17. 1 2 3 4 5 6 7 8 9 Saegesser, Marc A. "Apache Tomcat - Which Version Do I Want?". tomcat.apache.org. Retrieved 24 August 2018.
  18. ↑ Apache Tomcat Project. "Apache Tomcat" . Retrieved 21 September 2015.
  19. ↑ "The Jakarta Site - News and Status" . Retrieved 21 September 2015.
  20. ↑ Apache Tomcat Project. "Apache Tomcat" . Retrieved 2022-03-28.
  21. ↑ "[ANN] Apache Tomcat 6.0.10 released" . Retrieved 21 September 2015.
  22. ↑ "Apache Tomcat - End of life for Apache Tomcat 6.0.x". tomcat.apache.org. Retrieved 2020-07-20.
  23. ↑ Apache Tomcat Project. "Apache Tomcat" . Retrieved 21 September 2015.
  24. ↑ "Apache Tomcat 7 (7.0.109) - Changelog". tomcat.apache.org. Retrieved 2021-06-17.
  25. ↑ "Apache Tomcat - End of life for Apache Tomcat 7.0.x". tomcat.apache.org. Retrieved 2020-07-20.
  26. ↑ Apache Tomcat Project. "Apache Tomcat" . Retrieved 5 October 2015.
  27. ↑ "Apache Tomcat - End of life for Apache Tomcat 8.0.x". tomcat.apache.org. Retrieved 2020-07-20.
  28. ↑ Apache Tomcat Project. "Apache Tomcat 8.5 Changelog" . Retrieved 2023-10-16.
  29. ↑ "Apache Tomcat - End of life for Apache Tomcat 8.5.x". tomcat.apache.org. Retrieved 2023-10-16.
  30. ↑ Apache Tomcat Project. "Apache Tomcat 9.0 Changelog" . Retrieved 2023-10-16.
  31. ↑ Apache Tomcat Project. "Apache Tomcat 10.0 Changelog" . Retrieved 2023-05-09.
  32. ↑ "Apache Tomcat - End of life for Apache Tomcat 10.0.x". tomcat.apache.org. Retrieved 2022-11-17.
  33. ↑ Apache Tomcat Project. "Apache Tomcat 10.1 Changelog" . Retrieved 2023-10-16.
  34. ↑ Apache Tomcat Project. "Apache Tomcat 11.0 Changelog" . Retrieved 2023-10-16.
  35. ↑ "Apache TomEE". Apache OpenEJB.
  36. ↑ "The Apache Software Foundation Announces Apache TomEE Certified as Java EE 6 Web Profile Compatible". MarketWatch. 4 Oct 2011.
  37. ↑ "Apache TomEE Web stack gains approval". InfoWorld. 7 Oct 2011.

Bibliography

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