Declaration

A declaration block contains Java variables and methods that are called from an expression block within the JSP file. Code within a declaration block is usually written in Java.

The syntax of a declaration is:

<%! declaration(s) %>

Step 1 Create new Dynamic Web Project

Step 1.1 Create New Project

Go to File->New->Others… Select Dynamic Web Project under Web category then click Next. TypeServletDemo or whatever name you want in the Project name field.

Step 1.2 Configure Target Runtime

  • Click New Runtime… button under Target Runtime.
  • Select Apache Tomcat v7.0. Click Next.
  • Click Browse button to specify Tomcat Server installation directory. The select the folder then click Ok.
  • Click Installed JREs… button to add/remove or edit JRE definition. Remove existing one; then click Add button to configure new one. Select Standard VM; then click Next. Click Directory button to select the root folder ofJDKinstallation. Select the folder then click Ok. Click Finish.
  • Check the JDK then click Ok.
  • Change JRE to the JDK then click Finish.
  • Click Finish the finish the project creation.

Step 2 Create New JSP File

  • Right click to the project or WebContent folder, select New -> JSP File from the menu.
  • You can choose any name, for example declarationDemo.jsp
  • Click Finish.
  • Eclipse IDE will generate some boilerplate code. We just clear all its content and replace with the followings code:

Step 3 Configure Tomcat

Select Servers window; in case it’s not there, go to Windows -> Show View-> Others… Select Server -> Servers; then click Ok.

If this is the first time you are creating a server, in the Servers area you will see a link as No servers are available click this link to create a new server. Click the link.

Define a New Server window will be opened, In Select the server type. Select Apache -> Tomcat v7.0 Server. Then click Finish.

Step 4 Deploy The Application

  • Right click to the Tomcat Server select Add and Remove.
  • Move the application (JSPDemo) from Available column to Configured. Then click on Finish to deploy it to tomcat server.

Step 5 Start Tomcat Server

Right click on the tomcat server and choose Start or simply click on the green start icon to start the server.

Step 6 Run The JSP

We assume that you install tomcat on default port (8080) and project name is JSPDemo. Open web browser and type:

http://localhost:8080/JspDemo/declarationDemo.jsp

Output

Note: for JSP, you don’t need to Clean & Build the project or restart the tomcat server before running. You just change the code, save the changes and run.

For java classes, you need to Clean & Build the project to re-compile the code. In case register new servlet, change settings in web.xml or server.xml… you need to Clean & Build the project and restart tomcat server.