CaseSencitive

/* RULE: identofiers are case sensitive ( balance and Balance are two different) */

class CaseSencitive { public static void main(String[] args) { int bal; int Bal; System.out.println("legal identifiers"); } }

Illegel

/*
RULE: following are some illegel identifiers
*/

class Illegel
{
public static void main(String[] args)
{
int 7g;
int .j;
int -m;
int :b;
int s#;
int int;
int for;
int enum;
System.out.println("illegal identifiers");
}
}

DontUse

/*
RULE: dont use keywords as identifiers
*/
class DontUse
{
public static void main(String[] args)
{
int if;
int for;
System.out.println(" illegal start of expressition");
}
}

NoLimit

/*
RULE: there is no limit to the number of characters in the identifiers
*/

class NoLimit
{
public static void main(String[] args)
{
int asdf_hghighiggu_jhgjhghgu_kjghuge_njgh$jfhfghaf;
System.out.println("No Limit ");
}
}

After the first character

/*
RULE: After the first character ( $ or _ or character ) identifiers contains
any thing i.e numbers also
*/

class AfterFirst
{
public static void main(String[] args)
{
int a333424;
int _34we;
int $a23deu;
System.out.println("legal identifiers");
}
}

identifyrs starts with characters

/*
RULE: identifyrs starts with characters(a to z or A to Z)
or starts with underscore (_) and currency ($)
not starts with numbers
*/

class StartWith
{
public static void main(String[] args)
{
int $x;
int _a;
int m;
System.out.println("legal identifiers");
}
}

classes and interfaces

/*
RULE: classes and interfaces
the first letter of the word should be Capital and connectig word letter also capital
the name should be nouns
*/

class Dog
{
public static void main(String[] args)
{
System.out.println("Hello Dog!");
}
}

class PrintWriter
{
System.out.println("this is class");
}

interface Car
{
}
interface Runnable
{
}

Methods

/*
RULE: The first letter should be small letter and followed
words shold be capital letters
*/
class Methods
{
int getBalance(int accno)
{
System.out.prinln("balance is")
}
void setBalance(int acc,int amount)
{
}
public static void main(String[] args)
{

System.out.println("Hello World!");
}
}

Variables

/*
RULE: like methods rules
starting letter should be small then next word with capital letter
SUN recomended that it should be small ans good meaning full sound
*/

class Variables
{
public static void main(String[] args)
{
int buttonWidth;
int bal;
double accountNo;
System.out.println("legel convetions");
}
}

Constants

/*
RULE: constants are should be capital letters
they are used final and static keywords
*/

class Constants
{
static final double accountNumber=22323543;
public static void main(String[] args)
{
final float PI=22.7f;
System.out.println("legel constant code convention");
}
}