What is java?
java is the sum developed a programming language, after Oracle acquired, and then go through a series of development
iava has a simple and effective, portable, object oriented, interpreted, for distributed computing, with good performance, robust and take preventive measures multi-threading capabilities, with high security, dynamic languages, a neutral structure, no platform and other characteristics.
notes
10%3=1
-10%3=-1
10%3=1
-10%-3=-1
Class name capitalized
Low to high-precision automatic type conversion accuracy, precision cast to a low accuracy
&& short-circuit and as long as the current item is false, it does not determine the future, direct think the expression is false
| | logical or also known as short or as long as the current item is true, it does not determine the future of the direct expression of thought true formula
The basic concepts of object-oriented
There are three characteristics of object-oriented encapsulation, inheritance, polymorphism
Class contains state behavior
the object is a concrete
class is abstract
Class actually represent some of the basic features of a certain group of abstract objective world
Class Name Object Name = null; // declare the object
object name = new class name () // instantiate the object, as long as the new keyword it means opening up new heap memory space
The stack is the address of heap space