CCNA, CCNP, MCSA, CCNA Final Exam, All Answer Test Module With 100/100

Is it possible to automatically detect, which certificate was used for signing APK? I'd like to have both debug and release Maps certificates in application and pass valid one to MapView constructor.

In php what do you mean by function overloading and function overriding. and what is the difference between both of them? couldn't figure out what is the difference between them.

Does anyone know how I can take a mysql datetime stamp, such as YYYY-MM-DD HH:MM:SS and either parse it or convert it to work in JavaScript's Date() function, such as.. Date('YYYY, MM, DD, HH, MM, SS);

I know, I know, title is quite bad, but I'll try to explain what I mean here. So, I ask my members to show their photos. They upload it somewhere, then paste their photos' URL into input and I save it to my database (MYSQL). Then, the photo is being seen on their profiles. I get the URL from database and do something like that: <img src="<?=$photo;?>" height="123px" width="123px">"> where $photo is URL taken from MYSQL. Is it totally safe? Can somebody upload for example .php file and harm my website? Do I need to check if URL's ending is .gif, .png, .jpg?

So everyone says that sessions have security risks, I want to know what kind of risks are these? What can hackers do with sessions?

I was surprised to learn today that PHP is used widely in high-traffic websites.

I would like to write a Java terminal application that does screen manipulation. Are there any good libraries out there that allow you to manipulate the screen like curses in the *nix/C world?