javax.xml.bind.MarshalException

javax.xml.bind.MarshalException
 - with linked exception:
[com.sun.istack.SAXException2: unable to marshal type "com.javaxp.Employee" as an element because it is missing an @XmlRootElement annotation]
at com.sun.xml.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:331)
at com.sun.xml.bind.v2.runtime.MarshallerImpl.marshal(MarshallerImpl.java:257)
at javax.xml.bind.helpers.AbstractMarshallerImpl.marshal(AbstractMarshallerImpl.java:96)
at com.hewitt.ws.Test.marshalIt(Test.java:74)
at com.hewitt.ws.Test.displayEmpl(Test.java:58)
at com.hewitt.ws.Test.main(Test.java:28)
Caused by: com.sun.istack.SAXException2: unable to marshal type "com.hewitt.ws.Employee" as an element because it is missing an @XmlRootElement annotation
at com.sun.xml.bind.v2.runtime.XMLSerializer.reportError(XMLSerializer.java:244)
at com.sun.xml.bind.v2.runtime.ClassBeanInfoImpl.serializeRoot(ClassBeanInfoImpl.java:303)
at com.sun.xml.bind.v2.runtime.XMLSerializer.childAsRoot(XMLSerializer.java:490)
at com.sun.xml.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:328)
... 5 more

The process of convesrting a Java object to XML is known as Marshalling.

If you get above error, check for annotation @XmlRootElement in the class for which you are trying to do Marshalling. To know more, please see the example - JAXB marshalling and unmarshalling Hello World Example

Example - 

@XmlRootElement
public class Employee {
...
}

java.lang.NoClassDefFoundError: com/sun/istack/localization/Localizable

java.lang.NoClassDefFoundError: com/sun/istack/localization/Localizable
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2818)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1148)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1643)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2818)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1148)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1643)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389)
at java.lang.Class.getConstructor0(Class.java:2699)
at java.lang.Class.newInstance0(Class.java:326)
at java.lang.Class.newInstance(Class.java:308)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:119)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4618)
at org.apache.catalina.core.StandardContext$1.call(StandardContext.java:5184)
at org.apache.catalina.core.StandardContext$1.call(StandardContext.java:5179)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

If you get above error, you may need to add jaxb-core.jar in your applications classpath. You can download the file (example - jaxws-ri-2.2.8.zip file) from https://jax-ws.java.net/

Implementation of Restful Webservice with image

In Java EE 6, JAX-RS provides the functionality for Representational State Transfer (RESTful) web services. REST is well suited for basic, ad hoc integration scenarios. RESTful web services, often better integrated with HTTP than SOAP-based services are, do not require XML messages or WSDL service–API definitions. Before proceeding please read this article, Developing RESTful Web Services with JAX-RS.

Also please have look at the tutorial about "JAXB marshalling and unmarshalling", as it would be helpful to understand Restful Webservice.

For running this example, below mentioned particulars are used.

• Tomcat 7.0.11
• JDK 1.5
• MyEclipse 8.6.1

1. Create a new Web Service Project, File -> New -> Web Service Project

Java program to download file from url

Below is the java program to download a file from url.

Java code to send meeting request using iCal4j

iCalendar is a computer file format which allows Internet users to send meeting requests and tasks to other Internet users, via email, or sharing files with an extension of .ics. Recipients of the iCalendar data file (with supporting software, such as an email client or calendar application) can respond to the sender easily or counter propose another meeting date/time.

iCalendar is used and supported by a large number of products, including Google Calendar, Apple iCal,IBM Lotus Notes,Yahoo Calendar, Microsoft Outlook etc

iCal4j is an API which is used to modifying existing iCalendar data or creating new iCalendar data. To know more about iCal4j, click here.

About the example 

This example is straight forward, we will create a calendar (net.fortuna.ical4j.model.Calendar) object and add a Meeting event to it. You can set various properties to the event like subject, location, description etc. Obviously you can customize it according to your requirement. This example will generate a .ics file (TestCalendar.ics). You can send this generated file via email to interested parties. Please see the below self explanatory java program.

For running below example you will need to add below mentioned JAR files in your classpath.

• ical4j-1.0.3.jar
• backport-util-concurrent-3.1.jar
• commons-logging-1.1.1.jar
• commons-lang-2.6.jar

To download the above JAR file, click here.