Primitive and Object Type Instance Variables : variable scope « Java Source And Data Type « SCJP

Instance variables are variables defined at the class level. 
Instance variables are initialized to a default value each time a new instance is created

Default Values for Primitives and Reference Types

Variable Type                Default Value

Object reference             null (not referencing any object)

byte, short, int, long       0

float, double                0.0

boolean                      false

char                         '\u0000'

1.26.variable scope
1.26.1.Variable Scope
1.26.2.Attempting to access an instance variable from a static context.
1.26.3.Attempting to access a local variable from a nested method.
1.26.4.Attempting to use a block variable after the code block has completed.
1.26.5.Primitive and Object Type Instance Variables
1.26.6.Initialization Blocks