Relation between Tomcat and JDK Versions and Characteristics of Tomcat Versions

Apache Tomcat is an open source software that implements Java Servlet and Java Server Pages technologies. Different versions of Servlet and JSP specifications can use different versions of Apache and Tomcat. The correspondence between Tomcat and JDK versions is:

Servlet规格	JSP规范	EL规格	WebSocket规范	JASPIC规格	Apache Tomcat版本	最新发行版本	支持的Java版本
4.0	2.3	3.0	1.1	1.1	9.0.x	9.0.27	8及更高版本
3.1	2.3	3.0	1.1	1.1	8.5.x	8.5.47	7及更高版本
3.1	2.3	3.0	1.1	不适用	8.0.x（已取代）	8.0.53（已取代）	7及更高版本
3.0	2.2	2.2	1.1	不适用	7.0.x	7.0.96	6及更高版本 （WebSocket为7及更高版本）
2.5	2.1	2.1	不适用	不适用	6.0.x（已归档）	6.0.53（已归档）	5及更高版本
2.4	2.0	不适用	不适用	不适用	5.5.x（已存档）	5.5.36（存档）	1.4及更高版本
2.3	1.2	不适用	不适用	不适用	4.1.x（已归档）	4.1.40（已归档）	1.3及更高版本
2.2	1.1	不适用	不适用	不适用	3.3.x（已存档）	3.3.2（已存档）	1.1及更高版本

These versions are described in detail below to help you determine which version is suitable for you. For more details about each release, see the relevant release notes.

Note that although we provide downloads and documentation for older versions, such as Apache Tomcat 7. x, we strongly recommend that users use the latest stable version of Apache Tomcat wherever possible. We recognize that upgrading across major versions may not be easy, and there is still some support in the list for users of older versions. However, because of the community-driven support approach, the older your version is, the fewer people will be interested in or able to support you.

Alpha / Beta / Stable

There are three main versions of Tomcat, and the initial release of major versions usually ranges from Alpha to Beta to Stable

The Alpha version may contain a large number of untested/missing features and/or major errors required in the specification, and is not expected to run stably for any time period.

The Beta version may contain 1 untested feature and/or many relatively minor bugs. The Beta version is not expected to run stably.

The Stable version may contain a small number of relatively minor errors. The stable version is intended for production purposes and is expected to run stably for a longer period of time.

Apache Tomcat 9.x

Apache Tomcat 9. x is the current development focus. It builds on Tomcat 8.0. x and 8.5. x and implements the Servlet 4.0, JSP 2.3, EL 3.0, WebSocket 1.1, and JASPIC 1.1 specifications (versions required by the Java EE 8 platform). In addition, it also includes the following important improvements:

Adding support for HTTP/2 (required to run on Java 9 (since Apache Tomcat 9.0. 0.M18) or the Tomcat Native library being installed) Added support for TLS support using OpenSSL for JSSE connectors (NIO and NIO2) Added support for TLS virtual host (SNI)

Apache Tomcat 8.x

Apache Tomcat 8.0. x builds on Tomcat 7.0. x and implements Servlet 3.1, JSP 2.3, EL 3.0, and WebSocket 1.1 specifications. In addition, it also includes the following important improvements:

A single 1 common resource implementation to replace multiple resource extensions provided in earlier versions.

Apache Tomcat 8.5. x supports the same Servlet, JSP, EL, and WebSocket specification versions as Apache Tomcat 8.0. x. In addition, it implements the JASPIC 1.1 specification.

It was derived from the milestone release of Tomcat 9.0. 0. M4 (alpha) in March 2016. It provides HTTP/2 support for the Tomcat 9. x code base and other features, while compliant with Tomcat 8.0 runtime and specification requirements. (A stable version of Tomcat 9.0 could not be created at that time, and the Java EE specification for Tomcat 9 was determined several years later).

Tomcat 8.5 is considered a substitute for Tomcat 8.0. See the Migration Guide for instructions on migrating to Tomcat 8.5.

Apache Tomcat 8.5. x includes the following important improvements:

Adding support for HTTP/2 (requires Tomcat Native library) Added support for TLS support using OpenSSL for JSSE connectors (NIO and NIO2) Added support for TLS virtual host (SNI)

The following technologies have been removed from Apache Tomcat 8.5. x:

BIO Implementation of HTTP and AJP Connectors Support Comet API

Tomcat 8.5 has undergone significant changes in many areas, resulting in improved performance, stability and total cost of ownership. For more information, refer to the Apache Tomcat 8.5 Change Log.

Users of Tomcat 8.0 should be aware that Tomcat 8.0 is now out of development. Users of Tomcat 8.0. x should upgrade to Tomcat 8.5. x or later.

Apache Tomcat 7.x

Apache Tomcat 7. x builds on improvements to Tomcat 6.0. x and implements the Servlet 3.0, JSP 2.2, EL 2.2, and WebSocket 1.1 specifications. In addition, it includes the following improvements:

Web Application Memory Leak Detection and Prevention Improving Security for Manager and Host Manager Applications Universal CSRF protection Support to include external content directly in Web applications Refactoring (connector, lifecycle) and a lot of internal code cleaning

Apache Tomcat 6.x

Apache Tomcat 6. x builds on improvements to Tomcat 5.5. x and implements the Servlet 2.5 and JSP 2.1 specifications. In addition, it includes the following improvements:

Memory usage optimization Advanced IO functionality Reconstruct cluster

Users of Tomcat 6 should know that Tomcat 6 is now out of development. Users of Tomcat 6. x should upgrade to Tomcat 7. x or later.