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variable
subject			fact

variable	can be accessed by other variables and methods in any class in the same package by default
	can contain different classes of objects depending on the type of the variable
	can contain only values that are of the same type as the variable or a subtype of the variable's type
	can have an interface as its type which means that, with the variable, you can invoke any operation supported by the interface
	can refer to a particular object, several different objects during the execution of a program, or no object at all
	has definition An item of data named by an identifier
	has 1 value at any one time which is the object or class or primitive datum that it refers to
	has 1 name
	has scope which is the block in which it is declared
	has type
	has lifetime which is the time its block is being executed
	has purpose to refer to an object or a class or a primitive datum
	has scope
	has part value
	is a subtopic of Variables and Data Types
	is declared by giving the data type followed by the name of the variable
	is destroyed in the block where it is declared
	is partitioned into member variable, local variable, formal parameter
	is a kind of access unit
	may have access modifier public or private or protected
	refers to a class or an object or a primitive datum
	should be as private as possible
	should have comment if it is non-obvious
access unit	has access mode
syntactic unit	has syntax rule bold = mandatory italic = non-terminal normal font = optional

Kinds of variable :

• constant (4 kinds, 25 facts) (constant variable, final variable) - A variable with a value that never changes
• local variable (1 kind, 12 facts) - A data item known within a block but inaccessible to code outside the block, A variable that is declared in a method
• member variable (3 kinds, 53 facts) (field)
• operand (4 facts) (argument of an operator) - An input to an operator
• parameter (4 kinds, 28 facts) (argument, formal parameter) - A variable that transmits a primitive datum or object reference to a method or constructor
• pointer (5 kinds, 25 facts) - A variable that is used to store an address
• private variable (3 facts) - A variable declared with the private access modifier
• public variable (3 facts) - A variable declared with the public access modifier
• variable declared as a non-primitive data type (1 kind, 9 facts)
• variable declared as primitive data type (5 facts)
• variable with no access modifier (3 facts)

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