Outdated: Compilation Errors with JDK 1.4

JSP Tutorials - Herong's Tutorial Examples

∟Outdated: Compilation Errors with JDK 1.4

This section describes the compilation error on a JSP page that tries to use the 'page import' directive element to import a JavaBean class declared without package name.

To demonstrate the Tomcat error, let's review my FirstBean.java class again:

/**
 * FirstBean.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
public class FirstBean {
  private String text = "null";
  public String getText() {
    return text;
  }
  public void setText(String text) {
    this.text = text;
  }
  public String getInfo() {
    return "My JavaBean - Version 1.00";
  }
}

Here is the JSP page, FirstBean.jspx, that uses my FirstBean class:

<?xml version="1.0"?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="1.2">
<!-- FirstBean.jspx
 - Copyright (c) HerongYang.com. All Rights Reserved.
-->
<jsp:directive.page contentType="text/html"/>
<html><body>
<jsp:directive.page import="FirstBean"/>
<jsp:useBean id="b" class="FirstBean"/>
<jsp:setProperty name="b" property="text" value="Hello world!"/>
Property from my Bean:
<jsp:getProperty name="b" property="text"/>
<br/>
Info from my Bean:
<jsp:expression>b.getInfo()</jsp:expression>
</body></html>
</jsp:root>

To deploy the JavaBean class and the JSP page to the Tomcat server, run these commands in a command window:

>\local\j2sdk1.4.1\bin\javac FirstBean.java

>copy FirstBean.class
   \local\jakarta-tomcat-4.1.18\webapps\ROOT\WEB-INF\classes

>copy FirstBean.jspx \local\jakarta-tomcat-4.1.18\webapps\ROOT\

When visiting FirstBean.jspx with a Web browser, I do receive this compilation error:

org.apache.jasper.JasperException: Unable to compile class for JSP

An error occurred at line: 9 in the jsp file: /FirstBean.jspx

Generated servlet error:
    [javac] Compiling 1 source file

C:\local\jakarta-tomcat-4.1.18\work\Standalone\localhost
   \_\FirstBean_jsp.java:8: '.' expected
import FirstBean;

After reading the JDK 1.4 documentation, I found the root cause of the error. My FirstBean class was declared without any package name. So it is considered as in the unnamed package. JDK 1.4 added a new rule that does not allow an import statement to be used on classes in unnamed packages.