If you're just starting your career, and really care about it then you *need* to stay far away from Atlassian's "Graduate Developer" program. You might have had some other experience - open source experience, other jobs, freelancing, etc - but if you apply for that position then they'll only ever see you as a newbie university student and they'll always use that against you.
You might have an aptitude for programming, or you might just be really great at it - if so, good for you!
But, Atlassian is *not* the place for you to build your career if that's the case.
Say you join a team of Developers or Senior Developers, and you've been performing and working at the same level (or even higher) for over 12 months straight? Sorry, no promotion or career development for you. You were a "Graduate Developer". That means you're promoted based on the performance of *all the other Graduate Developers*, not based on what you do.
TL;DR: If you don't care about your career from the start, you're happy just to coast for years and have no desire to move forward, then this job is for you.
But, if you care about your career progression, you have a passion for software development and want to make the world a better place, then stay far away from their "Graduate Developer" program - they'll only stop you, halt you and won't ever recognize the good work that you do until maybe half a decade down the track they decide that you're a real developer and should be treated accordingly.