JSP executing .java file

Hi,
I have a small and simple question about JSP: can it either:
- compile a .java file and then execute (or interpret) the bytecode created ?
- execute a .class file ?
Thank you

ok nevermind,
found a good tutorial about this.
cheers

Similar Messages

Cannot Execute .java File..

Hi,i'm really confused about this..it's so weird..
i'm trying to execute (.java) file from another directory, but
it can't,why? if i just compile that file from another directory
there's no problem with that...
ex : i have file named Hello.java which i save it on C:\Work
i compile this file like this :
C:\javac C:\Work\Hello.java
there's no problem when i compile that file, but when i try to
execute that file i got this messages :
Exception in thread "main" java.lang.NoClassDefFoundError: C:\Work\Hello
this is how i execute that file : C:\java C:\Work\Hello
if i execute like this : C:\Work\java Hello, there's no problem..
Why (.java) file cannot be execute from another directory...
Thanks a lot..

It considers the pathname to be part of the class name when you do it like that, and since you don't have a class named C:\Work\Hello (and can't, since you can't use colons or backslashes in the name), that's not gonna happen.
Try this:
java -classpath C:\Work\ Hello
Note the space between C:\Work\ and Hello. Hope that helps :)

How can i execute "*.java " files in Workshop

Hi,
Im sunil,new to this weblogic workshop8.1..i dont know how to execute standalone .java files or servlets in workshop.plz help me and tell the way.
regards
Budati sunil

Im not too sure about the Java project. But single normal java files with public static void maain(String [] args) are very simple to execute.
1. Write the java code somewhere lets call this class A.
2. Make a dummy page flow.
3. In the begin action of this pageFlow, call the main method of the A class directly using A.main(null) since main is a static method. your code will work fine.
4. If you have to pass a String[] as parameters. Before calling main, create this String[] and then pass it.
In this way you can make a jsp and take the input from the user also.
Hope it helps
Cheeers

Where's the location of JSP's java files in weblogic

When I put *.jsp in my Web application,
          I can find the complied class in
          C:\bea\user_projects\mydomain\myserver\.wlnotdelete\extract\myserver_BOFT_BO
          FT\jsp_servlet\****.class
          But anyone can tell me where the ***.java?
          What's the location of these java files ?
          Samuel


In WL8.1, it appears that the .java files are placed in the same directory,
          but are removed after the class is compiled successfully. (Is there a
          setting to prevent the .java files from being deleted?)
          Try placing an intentional syntax error in your JSP file so that the
          compilation fails, and you should see the .java file where the .class file
          would have been.
          -- Craig
          "Samuel Hsu" <[email protected]> wrote in message
          news:3fc4365a$[email protected]..
          > When I put *.jsp in my Web application,
          > I can find the complied class in
          >
          C:\bea\user_projects\mydomain\myserver\.wlnotdelete\extract\myserver_BOFT_BO
          > FT\jsp_servlet\****.class
          > But anyone can tell me where the ***.java?
          > What's the location of these java files ?
          >
          > Samuel
          >
          >

How to get "Executable java file"?

Hi,
I wanted to get the .class file of my java programme for execution. i.e say "c:\java Abc ", I wanted to get "Abc" so that I can execute my file in my GUI like "java Abc".
Here is what I am doing
File file;
String command = "java";
Process p;
String classname = file.getPath(),fileName = file.getName();
p = Runtime.getRuntime().exec(command+" "+classname);
When I use this, I get the .java file. I wanted to get the "EXECUTABLE FILE ONLY", can any one help me?
Thanks

Put these lines after fileName = file.getName();
if (fileName.endsWith(".java"))
// Remove the .java extension from the filename
fileName = fileName.substring(0, fileName.length() - 5);
}

Send Data From JSP to java file

I'm trying to enter a name (username and password) in a JSP file and try to get that in a java class. The java class should read the username and print it out in the console.
JSP Page:
<html>
<body>
<form method="post" action="../adAuth/check/Validate">
     <table>
     <tr>
          <td>Username:</td>     <td><input type="text" name="username"></td>
     </tr>
     <tr>
          <td> </td><td><input type="submit"></td>
     </tr>
     </table>
</form>
</body>
</html>Java Code
package check;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Validate extends HttpServlet{
     public void doPost(HttpServletRequest request, HttpServletResponse response)
          String name= request.getParameter("username");
          System.out.println(name);
        public void doGet(HttpServletRequest request, HttpServletResponse response)
          doPost(request, response);
}When, I press the submit button, It is unable to find the java file (The webpage cannot be found - error appears) and hence nothing gets printed in the console. Any suggestions on what I'm doing wrong and how to rectify it ?
Edited by: Ramzey on Sep 8, 2010 11:24 AM

It should work fine. May be you need to check your servlet mapping attribute for any possible error.
If possible post your web.xml code.

Forward error to other jsp from .java file

Hi all
i have simple app
html with log in (username and passwor) and submit button
when the user click submit after he put his username and passwor the servelet will call loginHandler
now in logInHandler will forward to welcom.jsp if login and passwor are correct
but if not
will catch login exception
how can i forward to error.jsp ?
if i try to change the forward page<response.sendRedirect("/WEB-INF/pages/error.jsp")>;
i got this error
"Cannot forward after response has been committed"

You get that error when response headers have already been sent to the client (browser). This can happen in two ways that I know of:
- you flushed data to the client, or somewhere the data was automatically flushed
- you already did a redirect/forward and are attempting to do a second one.
So if you want to prevent yourself from getting the error, you'll need to make sure that neither of the situations has occurred. Don't output content unless you are absolutely certain that you won't need to foward/redirect later and don't do a redirect/forward twice in the same resource.

Starting exetutable java file from java code

Hi I was wondering how I can start a executable java file from java code?
thanks

Hi Mkaveli,
Yes, it's possible. If you have a JAR executable, you've just to call the main method of its starter class. For a simple executable class, just call its main method.
This way :
SomeStarter.main(null); // if there's no argumentSmall precision : the executable JAR or class must be specified in the classpath of your application.

How to access application vars into JavaBeans or Java File?

I have the application directory strcuture like this. I am using Apache Tomcat/6.0.14 and Eclipse IDE.
-/MyFirstServlet
-/MyFirstServlet/WebContent
-/MyFirstServlet/WebContent/WEB-INF/web.xml
-/MyFirstServlet/WebContent/web.jsp
-/MyFirstServlet/Src
     - com.model.DAO/userDAO.java (java class within package)
I have put following code into "web.xml".
==================================
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
     <display-name>
     MyFirstServlet
     </display-name>
     <context-param>
          <param-name>DBDriver</param-name>
          <param-value>com.microsoft.sqlserver.jdbc.SQLServerDriver</param-value>
     </context-param>
     <context-param>
          <param-name>connectionUrl</param-name>
<param-value>jdbc:sqlserver://localhost:1433;databaseName=MyFirstServletDB;user=hitesh;password=hit
esh;</param-value>
     </context-param>
     <welcome-file-list>
          <welcome-file>index.html</welcome-file>
          <welcome-file>index.htm</welcome-file>
          <welcome-file>index.jsp</welcome-file>
          <welcome-file>default.jsp</welcome-file>
     </welcome-file-list>
</web-app>
I am easily able to access from "web.jsp"
===================================
String DBDriver = application.getInitParameter("DBDriver");
out.println("<br>DBDriver:==="+DBDriver);
String connectionUrl = application.getInitParameter("connectionUrl");
out.println("<br>connectionUrl:==="+connectionUrl);
BUT when I try to access withing userDAO.java it gives "application is not resolved"
========================================================================
String DBDriver = (String)application.getInitParameter("DBDriver");
NOTE: I understand I need to import some inbuilt java package which will allow to use applcation vars
within java class.
What is that package? and how to do that?
Is there any other easy method to use global/application vars which can be used in all
JSP/JavaBeans/Java files?
Thanks in advance.

It might be easier to put that code somewhere else. JSP's are for presentation, not for accessing databases, business logic, etc.

*.exe Java File

Hi
I made a java application using JCreator LE which i always need to use and always need to run to get some critical output , so what i need to know is that if i can create an executable java file like in windows( .exe File) which when i click on it will pop up my application instead of always compiling and running it in the JCreator software.

Thanks for the reply , but by the way i've tried to
create an executable jar but the commands specified
to create an executable jar is not running in my
command prompt , they do nothing1) JCreator might be able to do that, too
2) I don't believe they do "nothing". Either they provide the JAR or an error message

How to execute java batch file in JSP

Kindly give a solution. I want execute a batch file which gives a preview window ,. I want call that batch file in my jsp, .I am using Tomcat 5.5, I have tried that using a Process object and Runtime.getRuntime().exec(path) , where path is location of my batch file. As a java class i could execute the batch file, but when i import the method in JSP nothing is happening (even no jsp error).
Is it possible to execute the batch file in JSP?
Can any one help me?

itsdhanasaraa wrote:
But as this a web application ... By using Runtime i'm getting some probs ..
Let me guess, you want your web application to run a program on the client and to your surprise that's not working?
Ain't gonna happen.
its taking more time to execute .... that's y is there any other option to execute .exe file other than Runtime.getRuntime().exec("filename");Write proper English and you may be taken more seriously.
1) it's not "taking more time to execute", whatever that's supposed to mean.
2) there's no other way to execute something. Not that you should every use even that way anyway
3) whenever you start thinking of executing external programs from Java, start thinking of not using Java in the first place.

How to execute a file using jsp or java

hi..
i had a jsp file as front end with start and stop button,
if i click the start button a file on my pc should execute.
if stop button is clicked the file should stop execution.
Any one know how to do this..especially how to run a file in ur system using java..
Thanks in advance

thanks for u r quick replies...
Actually i want to run a file on a client machine
only...
Okay.
for example, a client should execute a file which is
in another client...
This is not the same thing as what you just said.
can u tell me the method to execute the file......java.lang.Runtime.exec

Java File and JSP Page

I am to create a link verification program -- a simple java file with the database connection & some business logic and a JSP page that instantiates the my java file. It won't work. Everytime I run the jsp page, it gives me java.lang.NullPointerException. Can anyone give me some directions? The web server I am using is JRun.
Thank you
Below are my code:
JSP Page:
<%--      Verify Links
--%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<%@ page import="java.sql.*" %>
<%@ page import="java.net.*" %>
<%@ page import="pro.*" %>
<html>
<head>
<title>Results</title>
</head>
<body>
<%
try{
LinkConnection newconn = new LinkConnection();
newconn.initialize();
newconn.query();
newconn.close();
}catch (ClassNotFoundException cnfe)
out.println(cnfe);
catch (SQLException sqle)
out.println(sqle);
catch (NullPointerException npe)
out.println(npe);
%>
</body>
</html>
Java Code:
package pro;
import java.io.*;
import java.sql.*;
import java.net.*;
public class LinkConnection {
Connection con;
ResultSet RS;
Statement Stmt;
public void initialize() throws SQLException, ClassNotFoundException
Class.forName("oracle.jdbc.driver.OracleDriver");
con = DriverManager.getConnection("XXXX", "XXXX", "XXXX");
public void query() throws SQLException
Statement Stmt=con.createStatement();
String strSQL="Select guideline_name, guideline_url from pgt_guidelines";
ResultSet RS=Stmt.executeQuery(strSQL);
while (RS.next())
String guidelinename = RS.getString("guideline_name");
String guidelineurl = ("http://" + RS.getString("guideline_url"));
try {
URL url = new URL(guidelineurl);
HttpURLConnection link=(HttpURLConnection)url.openConnection();
System.out.println("<font color='blue'>");
System.out.println(guidelinename);
System.out.println("<br>");
System.out.println(guidelineurl);
System.out.println("</font>");
System.out.println("<font color='red'>");
System.out.println(link.getResponseCode());
System.out.println("</font>");
System.out.println("<br />");
          }catch (Exception e)
          {System.out.println("<font color='yellow'>Error Link </font>")
public void close() throws SQLException {
RS.close();
Stmt.close();
con.close();

i'm having the same problem, what is the solution to this
A Servlet Exception Has Occurred
java.lang.NullPointerException
     at test.Lesson.runSql(Lesson.java:80)
===== Lesson.java file =====
package test;
import java.sql.* ;
import java.io.Serializable;
public class Lesson {
     public Lesson( ) { }
//Line 9
     public String runSql ( ) {
          String browserOutput = "";
          Connection sqlca = null;
          Statement sqlStatement = null;
          ResultSet myResultSet = null;
//Line 16
          /* Connect to database, run SQL and produce output */
          try {
               /* Connection to the database */
               Class.forName("org.gjt.mm.mysql.Driver").newInstance();
               String theDatabase ="jdbc:mysql://localhost/employee";
               sqlca = DriverManager.getConnection(theDatabase,"usr","pwd");
//Line 24
               /* Construct and execute the sql, positioning before the
               first row in the result set */
               sqlStatement = sqlca.createStatement();
               myResultSet = sqlStatement.executeQuery
//Line 29
               ("select emp_id, " +
                    "emp_lname, " +
                    "city, " +
                    "state," +
                    "zip_code, " +
                    "emp_fname " +
                    "from employee " +
                    "where emp_id < 250 " +
                    "order by emp_lname, emp_fname");
//Line 39
               /* Construct the heading for the table */
               browserOutput =
                    "<div align=left>"+
                    "<table border=0 align=left width=520>" +
                    "<caption><i><b>" +
                    "Employee Listing</b></i></caption>" ;
//Line 46
               /* Construct the column headings for the table */
               browserOutput +=
                    "<th align=left>Emp_id</th>" +
                    "<th>First Name</th>" +
                    "<th>Last Name</th>" +
                    "<th>City</th>" +
                    "<th>State</th>" +
                    "<th>Zip</th>" ;
//Line 55
               /* Move to next row and & its contents to the html output */
               while(myResultSet.next()) {
                    browserOutput += "<TR><TD>" +
               myResultSet.getObject("emp_id").toString() + "</TD><TD>" +
               myResultSet.getObject("emp_fname").toString()+"</TD><TD>" +
               myResultSet.getObject("emp_lname").toString() + "</TD><TD>" +
               myResultSet.getObject("city").toString() + "</TD><TD>" +
               myResultSet.getObject("state").toString() + "</TD><TD>" +
               myResultSet.getObject("zip_code").toString() + "</TD></TR>" ;
//Line 66
               }//end of while
               sqlStatement.close();
               sqlca.close();
          }//end of try
          catch (SQLException e) {
//Line 72
               browserOutput = " Error: SQLException: " + e.getMessage();
               browserOutput= " Error: SQLState: " + e.getSQLState();
               browserOutput= " VendorError: " + e.getErrorCode();
          }//end of SQLException
          catch (Exception e) {
               browserOutput = " Error: JDBC Class creation: " + e.getMessage();
          }//end of Exception
/**Line 80**/     finally {
               try { sqlca.close(); }
               catch(SQLException e) {
               browserOutput = " Error: Closing connection: " + e.getMessage();
          }//end of finally
     /* Complete the html and return it to the Java Server Page */
     browserOutput += "</table>" + "</div>" ;
     return browserOutput;
     } //end of runSql
}//end of Lesson

Where does WL keep my Java files that it creates from JSPs?

Hi,
I'm using WL 9.2.2 on Solaris 9 (JDK 1.5). When WL builds a JSP page, it presumably converts those JSP pages to Java files before compiling them. Where does it keep those Java files? I'm having a hard time figuring out where my NullPointerException is occurring ...
java.lang.NullPointerException
at jsp_servlet._jsp._groups.__addgroup._jspService(__addgroup.java:810)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:283)
at weblogic.servlet.internal.ServletStubImpl.onAddToMapException(ServletStubImpl.java:394)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:309)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:175)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:525)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:261)
at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1085)
at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:398)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:241)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:283)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at com.myco.nps.im.plugin.NPSIMIntercepter.forwardRequestDirect(NPSIMIntercepter.java:852)
at com.myco.nps.im.plugin.NPSIMIntercepter.doFilter(NPSIMIntercepter.java:193)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3229)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2002)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:1908)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1362)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:181)
Thanks, - Dave

It deletes them by default. If you want to preserve them, set the "keepgenerated" and "working-dir" (this one so you don't have to hunt for them) elements in the "jsp-descriptor" element in the weblogic.xml file.
[http://e-docs.bea.com/wls/docs103/webapp/weblogic_xml.html#wp1038491]

Connecting java file to jsp

Hi i'm working on a jsp file and i want my jsp file to access the methods in a java file of mine.I have an idea its got something to do with beans. But i have no knowledge about beans. does anyone know how i can acheive it.

The following ( from the java tutorial with samples is downloadable) gave me the clarity in understanding how .jsp interact with classes (modified beans)
This tutorial is available at
http://java.sun.com
and follow thelinks for the tutorial.
Here Goes.....
Home | Download | PDF | API | FAQ | Search | Feedback | History
JavaBeans Components
JavaBeans components are Java classes that can be easily reused and composed together into applications. Any Java class that follows certain design conventions is a JavaBeans component.
JavaServer Pages technology directly supports using JavaBeans components with standard JSP language elements. You can easily create and initialize beans and get and set the values of their properties.
JavaBeans Component Design Conventions
JavaBeans component design conventions govern the properties of the class and govern the public methods that give access to the properties.
A JavaBeans component property can be
Read/write, read-only, or write-only
Simple, which means it contains a single value, or indexed, which means it represents an array of values
A property does not have to be implemented by an instance variable. It must simply be accessible using public methods that conform to the following conventions:
For each readable property, the bean must have a method of the form
PropertyClass getProperty() { ... }
For each writable property, the bean must have a method of the form
setProperty(PropertyClass pc) { ... }
In addition to the property methods, a JavaBeans component must define a constructor that takes no parameters.
The Duke's Bookstore application JSP pages bookstore.jsp, bookdetails.jsp, catalog.jsp, and showcart.jsp use the database.BookDB and database.BookDetails JavaBeans components. BookDB provides a JavaBeans component front end to the access object database.BookDBAO. The JSP pages showcart.jsp and cashier.jsp access the bean cart.ShoppingCart, which represents a user's shopping cart.
The BookDB bean has two writable properties, bookId and database, and three readable properties: bookDetails, numberOfBooks, and books. These latter properties do not correspond to any instance variables but rather are a function of the bookId and database properties.
package database;
public class BookDB {
private String bookId = "0";
private BookDBAO database = null;
public BookDB () {
public void setBookId(String bookId) {
this.bookId = bookId;
public void setDatabase(BookDBAO database) {
this.database = database;
public BookDetails getBookDetails() throws
BookNotFoundException {
return (BookDetails)database.getBookDetails(bookId);
public List getBooks() throws BooksNotFoundException {
return database.getBooks();
public void buyBooks(ShoppingCart cart)
throws OrderException {
database.buyBooks(cart);
public int getNumberOfBooks() throws BooksNotFoundException {
return database.getNumberOfBooks();
Creating and Using a JavaBeans Component
To declare that your JSP page will use a JavaBeans component, you use a jsp:useBean element. There are two forms:
<jsp:useBean id="beanName"
class="fully_qualified_classname" scope="scope"/>
and
<jsp:useBean id="beanName"
class="fully_qualified_classname" scope="scope">
<jsp:setProperty .../>
</jsp:useBean>
The second form is used when you want to include jsp:setProperty statements, described in the next section, for initializing bean properties.
The jsp:useBean element declares that the page will use a bean that is stored within and is accessible from the specified scope, which can be application, session, request, or page. If no such bean exists, the statement creates the bean and stores it as an attribute of the scope object (see Using Scope Objects). The value of the id attribute determines the name of the bean in the scope and the identifier used to reference the bean in EL expressions, other JSP elements, and scripting expressions (see Chapter 16). The value supplied for the class attribute must be a fully qualified class name. Note that beans cannot be in the unnamed package. Thus the format of the value must be package_name.class_name.
The following element creates an instance of mypkg.myLocales if none exists, stores it as an attribute of the application scope, and makes the bean available throughout the application by the identifier locales:
<jsp:useBean id="locales" scope="application"
class="mypkg.MyLocales"/>
Setting JavaBeans Component Properties
The standard way to set JavaBeans component properties in a JSP page is by using the jsp:setProperty element. The syntax of the jsp:setProperty element depends on the source of the property value. Table 12-3 summarizes the various ways to set a property of a JavaBeans component using the jsp:setProperty element.
Table 12-3 Valid Bean Property Assignments from String Values Value Source Element Syntax
String constant <jsp:setProperty name="beanName"
property="propName" value="string constant"/>
Request parameter <jsp:setProperty name="beanName"
property="propName" param="paramName"/>
Request parameter name that matches bean property <jsp:setProperty name="beanName"
property="propName"/>
<jsp:setProperty name="beanName"
property="*"/>
Expression <jsp:setProperty name="beanName"
property="propName" value="expression"/>
<jsp:setProperty name="beanName"
property="propName" >
<jsp:attribute name="value">
expression
</jsp:attribute>
</jsp:setProperty>
1. beanName must be the same as that specified for the id attribute in a useBean element.
2. There must be a setPropName method in the JavaBeans component.
3. paramName must be a request parameter name.
A property set from a constant string or request parameter must have one of the types listed in Table 12-4. Because constants and request parameters are strings, the web container automatically converts the value to the property's type; the conversion applied is shown in the table.
String values can be used to assign values to a property that has a PropertyEditor class. When that is the case, the setAsText(String) method is used. A conversion failure arises if the method throws an IllegalArgumentException.
The value assigned to an indexed property must be an array, and the rules just described apply to the elements.
Table 12-4 Valid Property Value Assignments from String Values Property Type Conversion on String Value
Bean Property Uses setAsText(string-literal)
boolean or Boolean As indicated in java.lang.Boolean.valueOf(String)
byte or Byte As indicated in java.lang.Byte.valueOf(String)
char or Character As indicated in java.lang.String.charAt(0)
double or Double As indicated in java.lang.Double.valueOf(String)
int or Integer As indicated in java.lang.Integer.valueOf(String)
float or Float As indicated in java.lang.Float.valueOf(String)
long or Long As indicated in java.lang.Long.valueOf(String)
short or Short As indicated in java.lang.Short.valueOf(String)
Object new String(string-literal)
You use an expression to set the value of a property whose type is a compound Java programming language type. The type returned from an expression must match or be castable to the type of the property.
The Duke's Bookstore application demonstrates how to use the setProperty element to set the current book from a request parameter in the database bean in bookstore2/web/bookdetails.jsp:
<c:set var="bid" value="${param.bookId}"/>
<jsp:setProperty name="bookDB" property="bookId"
value="${bid}" />
The following fragment from the page bookstore2/web/bookshowcart.jsp illustrates how to initialize a BookDB bean with a database object. Because the initialization is nested in a useBean element, it is executed only when the bean is created.
<jsp:useBean id="bookDB" class="database.BookDB" scope="page">
<jsp:setProperty name="bookDB" property="database"
value="${bookDBAO}" />
</jsp:useBean>
Retrieving JavaBeans Component Properties
The main way to retrieve JavaBeans component properties is by using the JSP EL expressions. Thus, to retrieve a book title, the Duke's Bookstore application uses the following expression:
${bookDB.bookDetails.title}
Another way to retrieve component properties is to use the jsp:getProperty element. This element converts the value of the property into a String and inserts the value into the response stream:
<jsp:getProperty name="beanName" property="propName"/>
Note that beanName must be the same as that specified for the id attribute in a useBean element, and there must be a getPropName method in the JavaBeans component. Although the preferred approach to getting properties is to use an EL expression, the getProperty element is available if you need to disable expression evaluation.
All of the material in The J2EE(TM) 1.4 Tutorial is copyright-protected and may not be published in other works without express written permission from Sun Microsystems.
hope this helps
regards,

JSP executing .java file

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