XML creation/parsing/validation & performance

Question

Hello friends. I'm faced with a situation in which I need to create and parse many relatively small xml documents. Most of the XML I will be exchanging is very simple, such as:
<? xml version="1.0"?>
<transactionId>12345</transactionId>
<accountId>98765</accountId>
<address>123 Main Street</address>
I have done enough research and prototyping to create and parse these simple documents using the DOM model. I have really started to wonder if I'd be better of simply hardcoding the creation and parsing of these documents. I'm getting some of these documents as a String over HTTP and then creating a DOM which I then can parse and am just not sure if what I am gaining in good programming practice is worth incurring the overhead of the DOM creation and parsing process.
I'm even more divided on the issue of using DTDs or XML Schemas to validate the structure of these tiny documents. I will be having to exchange a lot of these tiny XML messages and am comfortable with the fact that the parties I am trading XML with are not going to be changing things up on the fly.
On the other hand, I am a beginner in the XML world and am sure there could be a hundred things I haven't thought off.
I am grateful for any assistance.
CM

Answer 1

Also,
I assume that the values in you XML document are values from Java Objects, so why not have an interface defining a "toXml()" method for application classes to implement. All the classes would need to do is to know how to write its properties (variables) to an XML document. Again JDOM can handle his very easily... see below code....
/** method to return the entity properties as an XML string.
* @return the objects properties in an XML document String.
public String toXml() {
XMLOutputter out = null;
String xml = null;
Document document = new Document(new Element( "gallery-xml" ));
Element root = document.getRootElement();
Element content = new Element("gallery");
content.addContent(new Comment("Details of Gallery as an XML document"));
* Add attributes to xml document
DateFormat format = DateFormat.getDateInstance();
content.addContent(new Element( "image-id" ).addContent( getUUID() ));
content.addContent(new Element( "name" ).addContent( this.getImageName() ));
content.addContent(new Element( "student-name" ).addContent( this.getStudentName() ));
//content.addContent(new Element( "image-bytes" ).addContent( new String(this.getImageBytes()) ));
content.addContent(new Element( "image-file" ).addContent( this.getImageFile() ));
content.addContent(new Element( "date-created" ).addContent( format.format( this.getDateCreated() )));
content.addContent(new Element( "description" ).addContent( this.getDescription() ));
content.addContent(new Element( "subset" ).addContent( this.getSubset() ));
content.addContent(new Element( "year" ).addContent( this.getYear() ));
content.addContent(new Element( "course-id" ).addContent( this.getCourseId() ));
root.addContent( content );
//write to a string
out = new XMLOutputter(" ", true);
xml = out.outputString(document);
if (Logger.DEBUG) System.out.println( out.outputString( document ) );
return xml;