Archive for the Category ◊ Java ◊

Install Java on Linux Platform
Sunday, September 28th, 2008 | Author:

Download the JDK from http://java.sun.com/j2se/1.5.0/download.jsp
(A)  install jdk by running the RPM or bin file.

Installation Instructions

Install formats – JDK 5.0 is available in two installation formats.

  • Self-extracting Binary File – This file can be used to install the JDK in a location chosen by the user. This one can be installed by anyone (not only root users), and it can easily be installed in any location. As long as you are not root user, it cannot displace the system version of the Java platform suppled by Linux. To use this file, see Installation of Self-Extracting Binary below.
  • RPM Packages – A rpm.bin file containing RPM packages, installed with the rpm utility. Requires root access to install, and installs by default in a location that replaces the system version of the Java platform supplied by Linux. To use this bundle, see Installation of RPM File below.

Choose the install format that is most suitable to your needs.

more…

Category: Java, Linux Server Hosting |  Tags: , , | Comments off
Installing Tomcat on Linux
Sunday, September 28th, 2008 | Author:

To install apache tomcat , you need to install jdk (Java Development kit).
Tomcat need JAVA_HOME set properly before prior to operation or installation.
e.g.
JAVA_HOME=/usr/local/jdk
PATH=$JAVA_HOME/bin:$PATH

You can download the installer from
http://archive.apache.org/dist/jakarta/tomcat-5/v5.0.28/bin/jakarta-tomcat-5.0.28.tar.gz

Download version 5.0.28 to be compatible with JDK 1.4.2 because the latest versions of tomcat require JDK5

To extract and install Tomcat run this command:

]# tar xvfz jakarta-tomcat-5.0.28.tar.gz

The Tomcat files are installed in a directory called jakarta-tomcat-5.0.28 in the current directory.

Then you need to set CATALINA_HOME properly prior to start tomcat.

Use following command to set CATALINA_HOME and provide full path of tomcat directory (from toot).

export CATALINA_HOME=/user/local/jakarta/jakarta-tomcat-5.0.28

Run Tomcat

goto bin directory of tomcat
cd /user/local/jakarta/jakarta-tomcat-5.0.28/bin
]# ./startup.sh

Open web browser and type http://your_domain:8080/ you should see the Tomcat Administration page

Test Tomcat

go to webapps/ROOT in the tomcat directory and create page hello_world.html and write in it

Hello World

open the URL http://your_domain:8080/hello_world.html you should see your page.

Test JSP page

go to webapps/ROOT in the tomcat directory and create page test.jsp and write in it the following lines
<html>
<%=new String(“Hello World…”)%>
<br>
<%=new java.util.Date()%>
<br>
</html>

save and run the following URL http://your_domain:8080/test.jsp you should see Hello World.. followed by current date.

Monitor Tomcat

You can see the log file in the logs directory  /user/local/jakarta/jakarta-tomcat-5.0.28/log/

Stop Tomcat

Go to the tomcat bin directory and run command.

]# ./shutdown.sh

Note:- Apache Tomcat on Linux faster that tomcat in Windows at least 2 times in both startup, shutdown and in compiling jsp files.

Category: Java, Linux Server Hosting |  Tags: , , | Comments off
Thread Safety in JSP & Servlet
Sunday, September 28th, 2008 | Author:

You can thread safe your jsp (java server pages) pages in two ways

1. By implementing the SingleThreadModel interface.

This is done by adding the directive to your jsp page

<%@ page isThreadSafe=”false” %>

Within your jsp page.

When you implement SingleThreadModel interface instead of a single instance of the servlet generated for your jsp page loaded in memory, jsp engine creates new instance of that jsp page for each client request.
but avoid this method because, this methods has some performance issue and there are many pitfalls.

2. By using synchronized block or synchronized method

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