Java Basics

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Java Basics


These fundamentals to Java language are important because these terms and definitions will aid in the growth and
understanding of future java programming concepts. It is vital to have a basic grasp of fundamentals when discussing any
programming language.

Variables:

Source: Java variables

There are four kinds of variables in Java language: 

- Instance Variables: Are variables that are 'non-static', meaning the variable is unique to its  
class. Ex: the currentSpeed of one bicycle is independent from the currentSpeed of another.

- Class Variables (Static Fields): Any field declared with the 'static' modifier. This signifies that there is  
exactly ONE copy of this varaible in existence. 

- Local Variables:  Methods will use local variables to temporarily store its states. The determination of a 'local'  
variable is entirely dependent on where the variable is declared. Local variables are only visible to the methods in  
which they are declared; they are not accessable from the rest of th class.

- Parameters: Looking at 'public static void main(String[] args) <-- args is the parameter. 

Operators:

Source: Java Operators

- Operators are special symbols that perom specific operations on one, two, or three operands, and then return a  
result.

Expression, Statements, and Blocks:

Source:Java Expressions, Statements, and Blocks

Expression: An expression is a construct made up of variables, operators, and method invocations,  
which are constructed according to the syntax of the language, that evaluates to a single value.

Statements:  A statement forms a complete unit of execution.  

Blocks: A block is a group of zero or more statements between balanced braces and can be used  
anywhere a single statement is allowed.

Control Flow Statements:

Source: Java Control Flow Statements

Control flow statements break up the flow of execution by employing decision making, looping,  
and branching, enabling your program to conditionally execute particular blocks of code.