JAX-WS is mainly used for working with SOAP based web services and SOAP based web services are primarily based on XML: SOAP message (which is the format for message exchange in SOAP web services ) itself is XML and WSDL (which is the description of a SOAP web service) is also XML based. So we will discuss few important points about JAX-WS and XML.

XSD (XML Schema Definition), a recommendation of the World Wide Web Consortium (W3C), specifies how to formally describe the elements in an Extensible Markup Language (XML) document.

XSD can be used by programmers to verify each piece of item content in a document. They can check if it adheres to the description of the element it is placed in.

Example

<?xml version="1.0" encoding="UTF-8"?>

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"

Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format which is both human-readable and machine-readable. 

Example:

<?xml version="1.0" encoding="UTF-8"?>
<Employee>
  <id>001</id>
  <name>Jacob</name>
  <age>31</age>
  <salary>1000000</salary>
</Employee>

We have seen a dynamic lock ordering deadlock example previously.

Let us consider an example program that deadlocks, and then see how we could have avoided that. Below example is an example for a lock ordering deadlock.

The DeadLockExample class has two objects lockObject1 and lockObject2, which we will use as locks for synchronizing.

We will have two Runnables, which we will use for creating two threads: Runnable1 synchronizes on lockObject1 and try to get lockObject2, and Runnable2 synchronizes on lockObject2 and try to get lockObject1.