what is the java?|learn java free in one page,

What is the java? What is java programming Is it used for? History of java   Why need to invent java? Many features of java What …

what is the QR code? how free use Qr code

QR code is trends of need, you should know  what is the QR code?   how can we use it? even you use qr code in your daily life you…