Java from zero to hero
Java is a porgramming language that uses object oriented programming. By the way, object oriented porgramming (OOP) is a programming methodology used by software developers which conceive everything around this world as an object which interacts with other things by means of actions or methods. For instance, a person in programming world is seen an oject, your car, your windows, chair,house etc. are all object. I am quite sure you are getting confused with this new concept but I am conviced that you are going to be well as you keep on reading.
With this concept in mind of an object which performs a speficic action, a collection of objects and methods form a class. For example, in a plane, we have a business class and economic class. Passengers who pay for business class ticket enjoy the same facility and those for economic class as well. They perform action like eating, drinking, reading news papers, watching movies, sleeping etc.
Finaly, a collection of objects, methods and classes form a package in java or a library in other programming languages.