Master Java identifier naming rules and follow the specifications with ease

Java identifier naming rules: clear and easy to read, standardized and unified

In Java programming, identifiers are used to name variables and methods , class and package symbols. The choice of identifiers is critical to the readability and maintainability of your code. Following Java identifier naming rules can help you write clear, readable, standardized and unified code.

1. Identifiers consist of letters, numbers, underscores, and dollar signs

Java identifiers can consist of letters, numbers, underscores, and dollar signs. Among them, letters can be uppercase or lowercase, and numbers cannot be used as the first character of the identifier. For example, the following are valid identifiers:

name
age
_age
$age

2. The identifier cannot be a Java keyword

Java keywords are words with special meanings in the Java language , cannot be used as an identifier. For example, the following are Java keywords:

abstract
boolean
byte
case
catch
char
class
const
continue
default
do
double
else
extends
final
finally
float
for
if
implements
import
instanceof
int
interface
long
native
new
null
package
private
protected
public
return
short
static
super
switch
synchronized
this
throw
throws
transient
try
void
volatile
while

3. Identifiers cannot begin with numbers

Identifiers cannot begin with numbers. For example, the following identifiers are invalid:

1age
2name
3_age

4. The identifier cannot contain spaces

The identifier cannot contain spaces. For example, the following identifiers are invalid:

name age
age_name

5. The identifier cannot be the same as a Java reserved word

Java reserved words are words reserved in the Java language , cannot be used as an identifier. For example, the following are Java reserved words:

abstract
assert
boolean
break
byte
case
catch
char
class
const
continue
default
do
double
else
enum
extends
final
finally
float
for
goto
if
implements
import
instanceof
int
interface
long
native
new
package
private
protected
public
return
short
static
strictfp
super
switch
synchronized
this
throw
throws
transient
try
void
volatile
while

6. Identifiers should be descriptive

Identifiers should be descriptive so that other programmers can easily understand them its meaning. For example, the following identifiers are descriptive:

customerName
productName
orderDate

7. Avoid abbreviations for identifiers

Abbreviations for identifiers should be avoided because abbreviations may Making the code difficult to understand. For example, the following identifiers are difficult to understand:

custName
prodName
ordDate

8. Identifiers should avoid using underscores

Identifiers should avoid using underscores because underscores may cause The code is difficult to read. For example, the following identifiers are difficult to read:

_customer_name
_product_name
_order_date

9. Identifiers should follow camelCase

Identifiers should follow camelCase, i.e. each The first letter of a word is capitalized and the remaining letters are lowercase. For example, the following identifiers follow camel case:

customerName
productName
orderDate

10. Identifiers should follow a consistent naming style

Identifiers should follow a consistent naming style , so that other programmers can easily understand the code. For example, you can use the following naming style:

• ##Hungarian nomenclature: The variable name prefix indicates the type of the variable, for example:

  iAge represents the integer variable age
  sName represents the string variable name

• Pascal nomenclature: The variable name consists of words, each Capitalize the first letter of each word, for example:

  CustomerName represents the variable customerName
  ProductName represents the variable productName

• CamelCase nomenclature: The variable name is composed of words, the first letter of the first word is lowercase, and the first letter of the remaining words is uppercase, for example:

  customerName represents the variable customerName
  productName represents the variable productName

Code example:

public class Customer {

    private String customerName;
    private String customerAddress;
    private String customerPhoneNumber;

    public Customer(String customerName, String customerAddress, String customerPhoneNumber) {
        this.customerName = customerName;
        this.customerAddress = customerAddress;
        this.customerPhoneNumber = customerPhoneNumber;
    }

    public String getCustomerName() {
        return customerName;
    }

    public void setCustomerName(String customerName) {
        this.customerName = customerName;
    }

    public String getCustomerAddress() {
        return customerAddress;
    }

    public void setCustomerAddress(String customerAddress) {
        this.customerAddress = customerAddress;
    }

    public String getCustomerPhoneNumber() {
        return customerPhoneNumber;
    }

    public void setCustomerPhoneNumber(String customerPhoneNumber) {
        this.customerPhoneNumber = customerPhoneNumber;
    }

}

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