As someone who has worked on software patents and worked against software patents, there's nothing "stolen" here. What is happening here is a lawsuit making claims of patent infringement.

Since you haven't dealt with the software industry from the inside, here's a little perspective: Sometimes, companies patent algorithms and ideas in software that are blindingly obvious. Example: One company patented the algorithm of using a XOR of the bitmask of your mouse cursor as it moves across your screen. No one had done so previously because it seemed so stupidly obvious a technique. The prior art and obviousness of it did not prevent them from making the patent application. Another company patented the Lemple-Ziv compression algorithm that is used in so many "compression" programs today that I couldn't possibly count them all. By the time they got around to trying to enforce their patent, the horse was so far out of the barn that it was a futile task.

Here, the truth is that Sun could have sued Google for these supposed infringments, but they didn't. Patent lawsuits like this are hugely expensive, for both the plantiff and defendant. Oracle, however, is not above using lawyers to make money and they have a big pile of cash to fund their lawyers. Google has a huge pile of cash too. Oracle's management has looked at the accounting like this: suing a small company with little to no cash, no future prospects of making cash? Not worth it to sue. 

Sue Google, one of the biggest cash cows in the industry and a veritable money-printing company? Oh heck yes. There's coin to be made there.

Sometimes, there's only so many ways to skin the cat in software and computer systems engineering, and one ends up re-using a previously patented idea. That's not theft. It might be already patented, and then that's patent infringement, but it isn't theft.

Theft is when someone lifts the source code, verbatim, and puts it into their product. An example of this would be Huawei's copy of cisco's IOS being put into their clone routers. Huawei bowlderized the source code by going through and editing the names of various variables, functions, etc.... but there was a chunk of code in the DUAL routing algorithm that they could not make heads or tails of. Most people who looked at the code couldn't make sense of it, whether they were American or Chinese. It was an amazingly dense bit of code, walking across a complicated data structure in four dimensions.

Since I was one of the people who did understand it, I wrote a paragraph-long comment to explain what the code was doing, so that the reader had a chance of understanding what was going on.

Huawei left a couple dozen lines of C code alone, and they left that comment that I wrote alone as well. This was what was used to make the claim of source code theft in cisco's legal case. I'm sorta proud of that.