JDBC - Need to declare variables for values in insert statement

Do the declare statements and insert all have to be done in one statement
execute()?
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