I need to read an XML file using Java. Its contents are something like
C:/Input.csv
Check out Java's JAXP APIs which come as standard. You can read the XML in from the file into a DOM (object model), or as SAX - a series of events (your code will receive an event for each start-of-element, end-of-element etc.). For both DOM and SAX, I would look at an API tutorial to get started.
Alternatively, you may find JDOM easier/more intuitive to use.