Learn English – word for incorrect use of capital letters

I would write the first word after the period in capital case, as you did in the second sentence you wrote. The general rule of writing a word in capital case after a period is still valid even if you write a single word and then a period.

In those cases, the periods are used to give an emphasis to the single words. The pause when "reading" a period is longer than the pause used for a comma; for this reason I would not say the periods are like commas, in the examples you wrote.

As far as Java and Android SDK are concerned, they're proper nouns.

Object-oriented programming is often written as OOP. Perhaps the author of the sentence thought it should be capitalised because the abbreviated form OOP has capitalised letters. The proper way of writing it would be 'object-oriented programming', since it is in the middle of a sentence.

Design patterns should not have capitalised letters - it isn't a proper noun, neither does it have an abbreviation; the author may have capitalised it for emphasis. Or he just isn't familiar with the rules of this language that well!