As Jeanne said, 'Agile' isn't related with any particular language. It is a process/methodology on how the 'project' (which may be in java, .net for software engineer or even some construction or mechanical for other industries) is executed/moved ahead. Typically in our case, you first get 'requirements' and it called as 'requirement' phase, then design begins with 'design phase', then development(coding) and finally '
testing'(of the developed/coded product).
Agile is not this typical model, its more dynamic, 'everything' happens bit by bit, you get requirements(may not be the whole of it), you work on it, at the same time there will be testing people who would be preparing for testing(remember the code has not been written/completed yet). So you see all this phases move hand in hand... there are different agile methodologies, scrum is one such.
scrum