Variable initialization

Question

Hello guys,
Is there anybody know how and when java checks for variable initialization?For example if we change a value, assume a without initializing it we get variable a might not have been initialized.I wish to know how java checks that the variable is already assigned or not.
int a;
a++;//How java checks this
regards,
Haddock

Answer 1

Rules is:
To variables of instance - It's default value attribute automatically if not initialize with value.
To local variable (methods for example) - It's default value in initialization has been MUST attributed
Instance variables has a folliwing default value:
class A{
int i; //default value is 0
char c; //default value is '\u0000'
byte b; //default value is 0
short s; //default value is 0
long l; //default value is 0
float f; //default value is 0.0
double d; //default value is 0.0
boolean bl; //default value is false
String str; //Object is always null
int x[]; // null. It's Object's array
int x[5]; // 5 times default value 0.
void testInitializeValue(){
int x; // Compiler error; This variable has been initialized
if(x == 5){
return;
Ok..Thanks!!