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syntactic unit > access unit > variable > pointer > object reference > variable reference |
variable reference | ||||
subject | fact |
variable reference | is a subtopic of Variables and Data Types | |
is a kind of object reference | ||
object reference | has purpose to refer to an object indirectly so the object may be moved or reclaimed | |
is a key into the object table | ||
is a label for a chunk of memory that holds the memory address for a chunk of memory that holds and instance | ||
is not accessible to the programmer except for the equals method | ||
to cascade you prepend a class or package names to a reference with the character '.' | ||
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 1 value at any one time which is the 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 scope | ||
has part value | ||
is declared by giving the data type followed by the name of the variable | ||
is destroyed in the block where it is declared | ||
may have access modifier | ||
refers to a class or an object or a primitive datum | ||
should have comment if it is non-obvious | ||
access unit | has access mode | |
syntactic unit | has syntax rule bold = mandatory |
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