To invoke a java file before jsp

how to invoke a java file like servlet before jsp in adf.
.i want to write some custom methods in java file . I want to invoke it before jsp file .

Hi,
I think a servlet filter would be better suited than a servlet. However, if this in the context of e.g. JSF then a JSF Phaselistener is a much better approach
Frank

Similar Messages

Compiling / Running a Java file in JSP

Hi,
ok, I have a jsp page, which we will call page 1. Once I go to that page, I all I want it to do is compile a certain file.java, and then run the file.java. The user doesn't actually know that this is going on in the background. Page 1 automatically redirects the user to page 2 (also a jsp page).
The java program that I created (that was previously compiled and ran) creates a special javascript file. After running the file.java in page #1, the java file creates a javascript file that will be used in page 2 to display a tree node (group of information).
so, right now, I'm trying to figure out how to write the jsp code that will tell how to compile and run a java file. I was thinking about using javabeans before, but I think you HAVE to actually display the contents of the java file into the jsp (I think). Anyhow, thanks for the help!

sorry about being ambiguous before. What I mean by
running a java file was that I already created a java
file. I don't want to hava my java statements inside
the jsp file. I just want the jsp file have a command
in it that would call a java file, tell the java file
to compile and run. All the jsp file would do
(hopefully) is just give commands for a seperate java
file to compile and run. Thanks again for any help!Ok, so this other java file has some entry-point method, like main(), right? So call it...
<%
YourJavaClass.main(appropriateArgumentsGoHere);
%>
or better yet, it's an object you can use:
<%
YourJavaClass x = new YourJavaClass();
x.callSomeMethodHere(withAppropriateArgumentsHere);
x.callAnotherMethodMaybe();
%>
You don't need the jsp file to "compile" this java file, you'd already have compiled it beforehand, and it's class bytecode needs to be in your classpath (on the server side) of course.

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

Simple Question Calling methods from Java files through JSP without JVM

Hi.
I've got a simple question (forigve my newbieness)...
If I'm running Tomcat can I exectue a method in a compiled Java file from a JSP page without having the JVM installed on the server?
Any thoughts or additional comments would be appreciated.
Many thanks.

No... but that's because you can't run Tomcat without
a JVM installed on the server.
If you are running Tomcat, you are running a JVM for
the JSP pages to run in, in which case, yes, the JSP
pages can call the other Java code... as long as it's
in the classpath.Thanks a lot for the replies.
So just to check, if I sign up with a hosting company that offers Tomcat then the JVM will be installed on the server and I can call other Java code as long as it's in the classpath?
I just want to make sure before I sign up with a hosting company =D
Thanks again!

Import statement in .java files and .jsp files

Guys I have few mysteries about this import statement.
Please correct me if I am wrong.
1)Suppose if I have a folder c:\SourceFolder it has one.java and two.java files.If I compile one.java then one.class files is created in c:\ClassFolder .Now two.java uses one of the method of one.java,and without using import statement I am able to compile two.java, and two.class file is created in c:\ClassFolder.I assume that the path of one.class was taken from the CLASSPATH environment variable,hence I there was no need for import statement .........am i right ?
BUT... in My.jsp,which is in C:\JspFolder, if I want to use one.class,then I have to specifically import the class I want to use.That is i have to say
<%@page import="one"%>
and since the classpath is C:\ClassFolder ,it finds one.class in the C:\ClassFolder.(Note that My.class is created in a folder different from c:\ClassFolder )
But I am wondering why was there no need for me to import one.class in two.java.
(Note I am using JDeveloper and Apache server)
Please help.
In this case the pSo I am wondering in JSP why it doesn't take the class I am looking for from the classpath .
Help.

You have to understand Java scoping rules. In the 1st scenario with the two Java files I am guessing neither one of them begins with a package statement. This means that they belong to the default package. When you compile the compiler uses the classpath to resolve method calls looking in the default package since there was no import statement specified in two.java. JSP is a little different. Now I just read this here in these forums a couple of days ago. Since the classfiles generated from the JSP files are not in the CLASSPATH they are loaded by a different classloader. This is why you have to import all references to all classes in the default package.

Import statement in .java files and .jsp files ..correction

Guys I have few mysteries about this import statement.
Please correct me if I am wrong.
1)Suppose if I have a folder c:\SourceFolder it has one.java and two.java files.If I compile one.java then one.class files is created in c:\ClassFolder .Now two.java uses one of the method of one.java,and without using import statement in two.java I am able to compile two.java, and two.class file is created in c:\ClassFolder.I assume that the path of one.class was taken from the CLASSPATH environment variable,hence I there was no need for import statement .........am i right ?
BUT... in My.jsp,which is in C:\JspFolder, if I want to use one.class,then I have to specifically import one.class in My.jsp .That is i have to say
<%@page import="one"%>
in My.jsp.
and since the classpath is C:\ClassFolder ,it finds one.class in the C:\ClassFolder and MyJsp is compiled sucessfully.(Note that My.class is created in a folder different from c:\ClassFolder )
But I am wondering why was there no need for me to import one.class in two.java.
(Note I am using JDeveloper and Apache server)
Please help.

It has to do with packages. Most java classes are in a package, the name of which must conform to its place on the filesystem relative to the classpath. By that I mean that if you have com.mystuff.One.java, it must be in a folder com/mystuff where com is located somewhere in the classpath.
What you've done is a little different. I'm assuming a couple of things:
1. you have no package declaration at the top of one.java or two.java
2. you have the current directory "." in your classpath.
Java has the concept of the "default package", which covers classes without a declared package, and in your case is the current directory.
So when you're in c:\sourcefolder and run the compiler, then "."="c:\sourcefolder", and that directory is part of the default package. No import statements are necessary for classes that are in the same package. This is why two.java can call methods in one.java without an import statement.
When you run your jsp, the "current directory" part of your classpath is not c:\sourcefolder, but some other value (probably the directory you start your jsp engine from) You will have to import all non-java-library classes because the jsp itself becomes a java class, with a package that is determined by the jsp engine.

Using java class and variables declared in java file in jsp

hi everyone
i m trying to seperate business logic form web layer. i don't know i am doing in a right way or not.
i wanted to access my own java class and its variables in jsp.
for this i created java file like this
package ris;
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class NewClass{
    public static void main(String args[]){
        Connection con = null;
        ResultSet rs=null;
        Statement smt=null;
        try{
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            con=DriverManager.getConnection("jdbc:mysql:///net","root", "anthony111");
            smt=con.createStatement();
           rs= smt.executeQuery("SELECT * FROM emp");
           while(rs.next()){
            String str = rs.getString("Name");
            }catch( Exception e){
                String msg="Exception:"+e.getMessage();
            }finally {
      try {
        if(con != null)
          con.close();
      } catch(SQLException e) {}
}next i created a jsp where i want to access String str defined in java class above.
<%--
    Document   : fisrt
    Created on : Jul 25, 2009, 3:00:38 PM
    Author     : REiSHI
--%>
<%@page import="ris.NewClass"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1><%=str%></h1>
    </body>
</html>I wanted to print the name field extracted from database by ResultSet.
but it gives error cannot find symbol str.
please help me to find right way to do this.
i am using netbeans ide.

Very bad approach
1) Think if your table contains more than one NAMEs then you will get only the last one with your code.
2) Your String is declared as local variable in the method.
3) You have not created any object of NewClass nor called the method in JSP page. Then who will call the method to run sql?
4) Your NewClass contains main method which will not work in web application, it's not standalone desktop application so remove main.
Better create an ArrayList and then call the method of NewClass and then store the data into ArrayList and return the ArrayList.
It should look like
{code:java}
package ris;
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class NewClass{
    public static ArrayList getNames(){
        Connection con = null;
        ResultSet rs=null;
        Statement smt=null;
        ArrayList nameList = new ArrayList();
        try{
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            con=DriverManager.getConnection("jdbc:mysql:///net","root", "anthony111");
            smt=con.createStatement();
           rs= smt.executeQuery("SELECT * FROM emp");
           while(rs.next()){
            nameList.add(rs.getString("Name"));
           return nameList;
            }catch( Exception e){
                String msg="Exception:"+e.getMessage();
               </code><code class="jive-code jive-java"><font>return nameList;</code><code class="jive-code jive-java">
            }finally {
      try {
        if(con != null)
          con.close();
      } catch(SQLException e) {}
      </code><code>return nameList;</code>
<code class="jive-code jive-java">    }

Using java files with JSP

Ok, so im pretty new to this JSP lark and have a question.
I have Java Classes resting in .java files, i need to know how
do i link these files to my .jsp page so that the classes/variable etc.
declared with the java files are recognised when they are come
across in the .jsp file.
I dont know if I have explained that properly.

Just include this statement at the top of your jsp:
<%@page import="yourpackage.yourclass"%>
The .java files should of course be compiled into .class files prior to using (and you don't include the extension when importing).

How to invoke another Java file in Java program?

Hello all,
Now I am building a commnity of agents that can talk in Java, I have another Java-Based dialogue system to handle the dialogue between the agents. But I don'y know how to invoke the Java dialogue system file in the agent class.
Is there any methods can call another .java file in a Java program?
Help!!!!!please

Yep, vaguest of the vaguey vague vague.
Anyhoo,
I'm guessing you want to call a method from a different class?
Assuming you have the "Runner" class and then "Agent1", "Agent2", etc.
Agent1 whatever = new Agent1();

Problem accessing variables from java file to JSP page

Hello Everyone,
I have small problem accessing my method variables from my java bean file to a JSP page. can some please take a look and tell me why I can't populate my JSP page, I've been trying all day to get this done!!!
This is my Java file
package dev;
import java.io.*;
import java.util.*;
public class RoundDetail2
public String string_gameID;
public int string_card1;
public String readDetail_topLayer;
public static final String SUITS[] = {" ", "Clubs", "Hearts", "Spades", "Diamonds", "Joker", "FaceDown"};
public static final String VALUES[] = {"Joker ","Ace", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King"};
public static final String SuitVALUES[] = {" ","1","2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14"};
public RoundDetail2() throws FileNotFoundException
DataInputStream inFile=
             new DataInputStream(
                new BufferedInputStream(
               new FileInputStream("C:/apps/jakarta-tomcat-4.0.6/webapps/ROOT/WEB-INF/classes/dev/Data_452SY2.txt")));
try {
             while((readDetail_topLayer = inFile.readLine()) != null)
          StringTokenizer tokenizer_topLayer = new StringTokenizer(readDetail_topLayer,"\t", true);
               while (tokenizer_topLayer.hasMoreTokens())
                    string_gameID = tokenizer_topLayer.nextToken();
     catch(IOException e)
                System.out.println(e.getMessage());
     Thanks KT

......How are you declaring the class in your JSP? ... are you instantiating it as a bean using the useBean tag, or just instantiating it in your code like normal.
Maybe you could post the relevant JSP code too?
Hello again,
Only the last string is populating after the file has be tokenized. What I'll like to accomplish is passing the very first string in the file. I did not get too far in the JSP file setup because the code is still in it's testing stage, but any help will be highly appreciated.
Here is the JSP code
<%@page import="dev.*" %>
<%@page session="true" language="java" import="java.io.*" %>
<jsp:useBean id="wagerhist" scope="request" class="dev.RoundDetail2" />
<html>
<head>
<title>Round Detail</title>
<body>
<table width="530" bordercolor="#000000" valign="top">
    <tr>
          <td align="left" width="19%">Game ID<%=wagerhist.string_gameID%></td>
          <td align="left" width="30%"> </td>
          <td align="left" width="20%">card1</td>
          <td align="left" width="31%"> </td>
        </tr>
</table>
</body>
</html>

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,

How to write to log files using java files from JSP

Anybody knows different options in writing to log files using JSP?

Do you have an example?in the init() method of the servlet put the following
        FileOutputStream out = new FileOutputStream("your-log-file");
        PrintStream ps = new PrintStream(out);
        System.setOut(ps);
        System.setErr(ps);load the servlet on startup using <load-on-startup> in web.xml

Some compiling problem with java files in JSP

I wrote a file "ProductManager.java" to use the class of Product to do certain functions which are executed in a jsp, however, there are some curious errors.
C:\Tomcat\webapps\examples\WEB-INF\classes\com\wrox\begjsp\arrayexample3>javac P
roductManager.java
ProductManager.java:5: cannot resolve symbol
symbol : class Product
location: class com.wrox.begjsp.arrayexample3.ProductManager
private Product[] productList = new Product[3];
^
ProductManager.java:20: cannot resolve symbol
symbol : class Product
location: class com.wrox.begjsp.arrayexample3.ProductManager
public Product[] getProductList(){
^
ProductManager.java:28: cannot resolve symbol
symbol : class Product
location: class com.wrox.begjsp.arrayexample3.ProductManager
public Product getProductDetails(int prodid) {
^
ProductManager.java:5: cannot resolve symbol
symbol : class Product
location: class com.wrox.begjsp.arrayexample3.ProductManager
private Product[] productList = new Product[3];
^
ProductManager.java:13: cannot resolve symbol
symbol : class Product
location: class com.wrox.begjsp.arrayexample3.ProductManager
productList[0] = new Product(1,"Wrox Press Beginning JSP",49.99);
^
ProductManager.java:14: cannot resolve symbol
symbol : class Product
location: class com.wrox.begjsp.arrayexample3.ProductManager
productList[1] = new Product(2,"Wrox Press Professional JSP",59.99);
^
ProductManager.java:15: cannot resolve symbol
symbol : class Product
location: class com.wrox.begjsp.arrayexample3.ProductManager
productList[2] = new Product(3,"Wrox Press Beginning Java",39.99);
^
7 errors
Here is the source code:
Product.java
package com.wrox.begjsp.arrayexample3;
public class Product {
private int productId;
private String productName;
private double productPrice;
public Product(int prodid, String prodname, double prodprice) {
productId = prodid;
productName = prodname;
productPrice = prodprice;
public int getProductId(){
return productId;
public void setProductId(int ProductId){
this.productId = ProductId;
public String getProductName(){
return productName;
public void setProductName(String ProductName){
this.productName = ProductName;
public double getProductPrice(){ return productPrice; }
public void setProductPrice(double productPrice){
this.productPrice = productPrice;
ProductManager.java
package com.wrox.begjsp.arrayexample3;
public class ProductManager{
private Product[] productList = new Product[3];
private int productCount;
public ProductManager() {
initializeProductList();
private void initializeProductList() {
productList[0] = new Product(1,"Wrox Press Beginning JSP",49.99);
productList[1] = new Product(2,"Wrox Press Professional JSP",59.99);
productList[2] = new Product(3,"Wrox Press Beginning Java",39.99);
public Product[] getProductList(){
return productList;
public int getProductCount(){
return productList.length;
public Product getProductDetails(int prodid) {
int ProductIndex = -1;
for(int i=0;i<this.getProductCount();i++) {
if (prodid == productList.getProductId()) {
ProductIndex = i;
break;
if (ProductIndex != -1) {
return productList[ProductIndex];
} else {
return null;
Please tell me how to debug it to make it works, thx

add C:\Tomcat\webapps\examples\WEB-INF\classes to your classpath.
You can do this through the control panel or by:
set CLASSPATH=%CLASSPATH%;C:\Tomcat\webapps\examples\WEB-INF\classes

HELP NEED FOR INVOKING THE JAVA CODE INSIDE JSP

Hello,
any one knows how to Write a java code inside the .jsp files... please if any one knows it please ....help me .....

hi .
Use scriptlets , for example :
<html>
<%
int x;
for(x=1;x<=5;x++)
out.println(x);
%>
</html>

How to run and displaying output of java file in jsp page ???

Hai,
I am going to develop a website which would have everything about java.
Example code displayed for all methods.Next to every Example i shoud have *"Run"* button.
Click at Run button should compile the example and show the output or even error.
Ex:If the user clicks the vector link then all the examples will be shown..
import java.util.*;
etc...
Run button-onclick it shoud compile the code above and shoud show the output....
I don't know how to get the console error and output..
kindly help me out....Thanks.

Check java.lang.Runtime API.

To invoke a java file before jsp

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