XML : Read & Update XML Node element

I am a newbie to Java programming and trying to do an XML read and updation.

I was able to write a program in Java that will create the following XML file. There will be multiple staff in a XML file and the id's are unique. This example has 2 staff items.

  <?xml version="1.0"?>  <company>      <staff id="1001">          <firstname>yong</firstname>          <lastname>mook kim</lastname>          <nickname>mkyong</nickname>          <salary>100000</salary>      </staff>      <staff id="2001">          <firstname>low</firstname>          <lastname>yin fong</lastname>          <nickname>fong fong</nickname>          <salary>200000</salary>      </staff>  </company>    

What i want to do is,

Step - 1: Read XML - based on ID provided by user, find the corresponding staff element and read it's salary.

Step-2: Update XML - Change the salary item for the corresponding staff and save the file.

What am looking for is an efficient way of doing this!