JDBC - Need to declare variables for values in insert statement

That is, what is the scope of variables I declare?

I see a variety of syntax examples, some for older versions?

I'm using pg 9.2.2, so what are the rules/syntax for declaring and using variables?

Use case: I collect metadata from XML articles such as title, journalName, volume, year.  For each article I need to create a pg table record and insert the values for the various metadata items in the article.

This is my first post to this list.

Thanks,

 - Bob