Ivy Bridge will be a big bump and certainly an Ivy Bridge MacBook Pro will be a much more substantial bump from the current rev than the current Sandy Bridge rev was from the Early 2011 Sandy Bridge rev. It won't be as big of a bump as the Early 2011 rev was over the Mid 2010 rev, but it'll be faster, certainly. The Intel HD 4000 that'll come in tow with Ivy Bridge will be better than both the Intel HD 3000 and the NVIDIA GeForce 320M IGPs in all respects (from what I've heard about it); it'll still be an IGP, itself, and it'll still be an Intel one at that (which means it'll lag behind other contemporary IGPs and certainly discrete VRAM GPUs), but it'll be a better IGP than has ever been shipped in an Intel Mac (whether we're talking NVIDIA or Intel). That being said, most people on here assume that there'll be an exterior refresh. Personally, I disagree, but I am excited about USB 3 integration (given that Thunderbolt will never supplant USB, and that USB 3 support is inevitable on all machines at this point). So, take your pick. If you buy a current model, you won't hate it. They're fantastic machines. Personally, I'm going to wait until the next refresh so I have the choice between a new model or (if I hate what they do to the next refresh) a current one at a discounted price.
If you're just looking at a 13" and you're just looking at Java programming, the buy now vs. buy then argument gets interesting as there are all sorts of theories on the future of the 13" MacBook Pro, especially in light of the 13" MacBook Air's growing popularity and given Apple's seeming push toward ultra-portables. If you believe that the 13" MacBook Pro is endangered, I say buy now as a 13" Air won't grant you as much flexibility on how much RAM you can stuff in it (let alone HD/SSD upgrades down the road). If you don't believe that it is endangered, then I'd say that waiting couldn't hurt, given that another theory on the table is that the 13" MacBook Pro will be able to take a Quad-Core Ivy Bridge CPU due to breakthroughs in thermal output (or rather lack thereof).
If that doesn't matter to you, the current machine is fine. Plus, you probably have another six more months of the current line-up before we even get Ivy Bridge MBPs anyway given that MacBook Pros have an 8-10 month refresh cycle and it was last refreshed in late October. Again, stuff to think about.
I can't say which course of action is better; personally, with my own impending move from a complex set-up involving more computers than anyone really needs to just a beefy PC tower for gaming, and a decent Mac laptop for the rest of my digital (non-PDA/Smartphone/iPad) life, the 13" lacks way too much in the GPU department, and due to the nature of how small that machine is and how they do not have room to provide any kind of decent mobile GPU with discrete VRAM. So, I'm considering a higher-end 15" MacBook Pro for myself. But given that you are in the market for a 13" MacBook Pro, and given your intended uses for it, I don't think you can go wrong at this time no matter what you end up picking. Best of luck!
