Installing Oracle JDK in Amazon AWS EC2 Ubuntu

Lately I tried to install Oracle JDK in one of my Ubuntu servers on Amazon EC2 instance. Unfortunately the inbuilt installers support the installation of OpenJDK.

For some requirements, I was in need of installing a specific version of JDK and test my application, you could get the older version from Oracle Site. I used the following script from one of the blogs, hope it helps someone.

The Key here is Oracle need you to accept the license terms before using the any version of Oracle JDK. You could do the same from the scripting by just adding --no-cookies --no-check-certificate --header 'Cookie:gpw_e24=http://www.oracle.com; oraclelicense=accept-securebackup-cookie' params to the WGET.

Alternative, you could download the installers/zip files from external CDNs, like REUCON, move it to EC2 instance through SFTP and install it.

Errors running builder ‘JavaScript Validator’ on project

I got this annoying exception on every auto build of my Dynamic Web Project.

“Errors occurred during the build.
Errors running builder ‘JavaScript Validator’ on project ‘GenieAlert’.
java.lang.NullPointerException”

I was trying to stop the validation of Javascript in the Eclipse properties with the following options,

Windows -> Preferences -> Validation -> Client-side JavaScript Validator -> Checked Manual & Unchecked Build.

This option didn’t work out, then I realized that it happens only on the Build time. The following option came in handy to do that.

Project -> Properties -> Builders -> Unchecked ‘Javascript Validator’

Sometimes when you try to run the Web projects from eclipse on servers these JavaScript validation stops the deployment of the project on servers stating “JavaScript Validation Exception found”. I hope the above solutions will help in those situations too.

Create Web Services using Axis Java2WSDL, WSDL2Java and Eclipse for all Servers manually – Part 2

With all the basic configurations done as specified in the last Article we continue to develop the Business logic.

  1. Create a class named Calculator.java, place four public methods add, subtract, multiply and delete and place the appropriate logics in it.
  2. This is the class that has to be exposed as the Web Service and we write the funky TestRunner.java class to do all out operations like creating WSDL file, creating stub file etc.
  3. Generate WSDL file using Java2WSDL: Axis has a tool called Java2WSDL, which generates a WSDL file for a web service using a Java class. Java2WSDL file takes the following arguments.
    1. o – name for WSDL file -> calculator.wsdl
    2. n – target namespace -> mx:com.itechgenie.services.Calculator
    3. l – url of web service -> http://<host:port>/<Project-Name>/services/calculator

    Summing up the above arguments the following command line arguments is created.

    Read this Article on how to run the command line java tools from Eclipse.
    You can run the Java2WSDL as follows in the TestRunner class. Naah, don’t ask how, just put the following lines the main method and press CTRL + F11.

    The Java2WSDL class has the System.exit(0); method called from inside. So lines after the Java2WSDL will not be executed. To get the other arguments supported you can just run Java2WSDL.main(new String[0]) ;. This will display all the arguments supported by Java2WSDL Utility and this works for other utilities also.
    After running this Utility you will find the calculator.wsdl file created in the root folder of the Project.

  4. Generate Server side and Client side codes using WSDL2Java: WSDL2Java is another tools provided by the AXIS, which can generate server side and client side Java classes using a WSDL file. These classes are needed for deploying the web service and also for accessing the web service using a Java client. This tool expects the following argument which includes the WSDL file generated in the last step.
    1. o – output folder -> src
    2. p – package for generated classes -> mx:com.itechgenie.services. generated
    3. s – generate server side classes as well
    4. *.wsdl – WSDL file of any web service

    Summing up the above arguments the following command line arguments is created.

    Read this Article on how to run the command line java tools from Eclipse.
    Now run the WSDL2Java utility as follows.

    Once the above command is run, Just refresh the project in eclipse, you will find the following files created inside the “com.itechgenie.generated.service” package.

    1. Calculator.java
    2. CalculatorService.java
    3. CalculatorServiceLocator.java
    4. CalculatorSoapBindingImpl.java
    5. CalculatorSoapBindingStub.java
    6. deploy.wsdd
    7. undeploy.wsdd

    The above files can be used in both Server and Clients side as Skeleton (CalculatorSoapBindingImpl.java) and the Stub (CalculatorSoapBindingStub.java) respectively.

  5. Binding the business logic with the Skeleton: Take the Skeleton file and you will find the exact methods that were available in our Business logic class (Calculator.java.).
    Create a instance of the Business class and invoke the appropriate method from the skeleton as follows (Find the lines highlighted in yellow.).

    That’s it; we are now done with the development part of the Web Service. All we have to do is to configure to make the service up and running.
  6. Last configurations to make our service available: Open the server-config.wsdd file inside the WEB-INF folder. You will find the following lines.

    Keep the file aside and open the deploy.wsdd from the WSDL2Java generated files. Copy the <service> … </service> tag completely and paste in between the comments said above.
  7. Conclusion: You can follow the steps 6 to 11 and create as many services as you want and paste them in the server-config.wsdd.
    With this the configurations for the Web Service is over. Export the Project as a War and deploy it in Web Server and point to the URL http://<host:port>/<Project-Name>/services
  8. This URL should display all the services generated from steps 6 to 11 with the links the WSDL files for the above.

    Click here to download the sample project.

Create Web Services using Axis Java2WSDL, WSDL2Java and Eclipse for all Servers manually – Part 1

There a lot of Web Service implementations available in market. The most widely used among them is the Axis way of implementation. There are a lot of Examples available in the web to create expose, consume the Web services using the Axis packages. But it is not feasible to work get the Axis complete packages inside corporate offices all of a sudden and yes I faced the same situation.

After some investment of time I found some funky stuff in web to create a Web Service with just a couple of jars in hand and off-course with the help of Eclipse.

Prerequisites:

  1. Eclipse, any version should be ok, but I was using the Eclipse Indigo with Ant installed in it.
  2. The set of jars needed. Jars are included in the Project sample.
    1. axis.jar
    2. commons-discovery-0.2.jar
    3. commons-logging.jar
    4. jaxrpc.jar
    5. log4j-1.2.15.jar
    6. saaj.jar
    7. wsdl4j.jar
    8. The sample web.xml, server-config.wsdd (These will be used later in the development steps).

Steps to develop Web Services:

  1. Create a Dynamic Web Project “SampleWebService” in Eclipse.
  2. Place the above said jars in the WEB-INF/jars folder.
  3. Open the Web.xml file and copy the following contents into it somewhere between tags. These contents are available in the sample attached.
  4. Copy the server-config.wsdd next to web.xml file. We will reuse this file once again after complete the business logic of the server.
  5. Now the basic configurations are complete, we have to develop the business logic for the Web Service. In my example I have taken the Old school Calculator sample.
    Click here to go to the next Part of this article.

Dynamically adding HTML components using JavaScript

At times there will be requirements to dynamically add a scetion of HTML multiple times in UI. This can be achived by using JavaScript. One of the implementation for such a scenario is addressed in the following example.
Requirement:
In thie example, there was a need to add a row of three Text boxes, select box to be added dynamically to a page on a button click. Validation has to be done to the dynamically added rows.

Design & Usage:

The design of the sample goes like this.

There will be a container to hold the control items, like button to add the component, field to hold the counter. Following the control box an empty container to hold the dynamically added components. Another container just below this, to hold the contents that has to be created dynamically. The contents has to be formulated carefully with the layouts and identifications. To achive the easier identificaiton of the elements inside the components an auto generated ‘ID’ is added to all the elements on the go. To achive this a delimiter is added to all the elements. Here the delimiter used is “ADDIDHERE”. This will be replaced by the counter variable on the go.
Source:
View Sample page.
Download Sample.
Screenshot:

DynaComp

Simple methods to Create, Read and Delete Cookies using JavaScript

Usage:

1. createCookie(name,value,days) – Void function.

name – Name for the cookie to be created
value – Value of the cookie
days(INT – Non Madatory) – Number of days to keep the cookie in browser. If not specified the cookie will expire as soon as soon the browser is closed.

2. readCookie(name) – Returns the value of the cookie.

name – Name given at the time of creation

3. eraseCookie(name) – Void function.

Dependency – createCookie method should be in place.