5 to face questions per day (iv) Java basics

What is the difference between heap and stack?

A stack is a linear collection whose actions to add and delete elements should be completed in the same paragraph. The stack is processed in a last-in, first-out manner.
A heap is a constituent element of a stack

The difference between forward and redirect?

Forward is the server requests the resource, the server directly accesses the URL of the destination address, reads the response content of that URL, and then sends the content to the browser, the browser does not know where the server sends the content from, so its address bar is the original address.
Redirect is the server based on logic, send a status code, tell the browser to request the address again, in general, the browser will use all the parameters just requested again, so the session,request parameters can be obtained.

What is the difference between EJB and Java bean?

Java beans are reusable components, and there is no strict specification for Java beans, and in theory, any Java class can be a Bean. In general, however, because Java beans are created by containers (such as Tomcat), Java beans should have a parameterless constructor, and in addition, Java beans typically implement the serializable interface to implement Bean persistence. Java beans are actually equivalent to the local in-process COM component in the Microsoft COM model, which cannot be accessed across processes. Enterprise Java beans are equivalent to DCOM, which is distributed components. It is a Java-based remote method invocation (RMI) technology, so EJBS can be accessed remotely (across processes, across computers). However, EJBS must be in containers such as Webspere, WebLogic, and EJB clients never directly access real EJB components, but are accessed through their containers. The EJB container is the proxy for the EJB component, and the EJB component is created and managed by the container. The customer accesses the real EJB component through the container.

What is the difference between Static Nested class and Inner class?

Static Nested Class是被声明为静态（static）的内部类，它可以不依赖于外部类实例被实例化。而通常的内部类需要在外部类实例化后才能实例化。

What is the difference between a dynamic include and a static include in a JSP?

Dynamic include is implemented with the Jsp:include action, which always checks for changes in the contained files, is suitable for containing dynamic pages, and can take parameters.
Static include is implemented with the include pseudo-code and will not check for changes in the included files, and is suitable for containing static pages <%@ include file= "included.htm"%>

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5 to face questions per day (iv) Java basics