what are the differences between a Web container, Web server, servlet container and an application server?

Typically, a Web server refers to an execution infrastructure that handles HTTP requests and responses; a servlet container refers to a component that handles the lifecycle for servlets; an application server refers to a framework (servlet container, EJB container, JSP engine, MQ container, etc.) for handling Web applications. However, a Web container has a couple of meanings depending on the source. Most refer to a Web container as the part of an application server that manages servlets, JavaServer Pages (JSP) files, and other Web-tier components. Some refer to a Web container as the infrastructure for managing the lifecycle for Web services.