There are three different types of declared variables in Java. They are instance, class and local variables.
Instance Variables
Instance variables are the non-static fields of your class, often referred to simply as fields.
Primitive numeric fields initialize to 0. This includes byte
, short
, int
, long
, float
and double
.
boolean
s initialize to false
.
char
s initialize to the null character u0000
.
Reference types initialize to null
.
Class Variables
A class variable is a field within a class declared as static, often referred to as a static variable or static field. It is also same initialize as instance variable.
Local Variables
A local variable is a variable defined within a method, which includes any method
parameters.
Local variables must be initialized before use. They do not have a default value.
Initialization process is done by JVM when method is create.
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