Naming Standards - Java

Names should broadly reflect what a method or class does. Single meaningless words are not acceptable.

1. Basic Naming Conventions

Exception: acronyms like URL and HTML remain fully uppercase in class names.

// Correct
public class DateWork {
    private int remainDays = 10;  // remaining days

    public void calculateNameWithData(Data data) {}
}

// Wrong (meaningless abbreviations)
public class DateWork {
    private int r = 10;

    public void cal(Data data) {}
}

2. Naming Prohibitions

• Names must not start or end with an underscore _ or dollar sign $.
• Do not mix pinyin with English, and never use Chinese characters directly.
• Do not use completely non-standard abbreviations that are not self-explanatory.

// Wrong
public static final int max_stock_count = 20;  // constant not in ALL_CAPS
public static final int MAX_COUNT = 20;         // incomplete semantics

// Correct
public static final int MAX_STOCK_COUNT = 20;

3. Special Naming Rules for Classes

• Abstract classes: prefix with Abstract
• Exception classes: suffix with Exception
• Test classes: start with the name of the class under test, suffix with Test
• Domain models: suffixes such as DO, BO, DTO, VO remain uppercase

// Correct
UserDAO, ParameterNameSpace, NetworkHelper

// Wrong
userDAO, ParameternameSpace, NETworkHelper

4. Package Naming

Package names are all lowercase, with a single semantic word between each dot separator, in singular form:

// Correct
package com.fr.data.model;

// Wrong
package com.fr.chart.ChartAttr;       // contains uppercase letters
package com.finebi.common.internalimp; // multiple semantic words combined

5. Prefixes for set / get / is / has Methods

• Setting a property: setXxx()
• Getting a boolean property: isXxx() or hasXxx()
• Getting other properties: getXxx()

// Correct
public class Student {
    private boolean male;

    public boolean isMale() {
        return male;
    }
}

// Wrong
public boolean getMale() { ... }

Boolean field names must not start with is or has (this can cause serialization errors in some frameworks):

// Wrong
private boolean isMale;

// Correct
private boolean male;
public boolean isMale() { return male; }

6. No Magic Numbers — Use Named Constants

// Wrong
public double area(double r) {
    return 3.14 * r * r;
}

// Correct
private static final double PI = 3.14;
public double area(double r) {
    return PI * r * r;
}

7. Do Not Use "Custom" in Public Interface Names

A public interface already implies "customizable implementation" — there is no need to emphasize it:

// Correct
public interface PasswordHandleProcessor extends XMLable, Immutable {
    String encrypt(String clientPassword);
    String decrypt(String clientPassword);
}

// Wrong
public interface CustomPasswordCryptProcessor extends XMLable, Immutable {
    String encodePassword(String clientPassword);
    String decodePassword(String clientPassword);
}

8. Fluent Builder Methods That Return this Must Not Start with set

Provide two separate methods: a standard setter and a fluent method that returns this:

// Correct
public void setIp(String ip) {
    this.ip = ip;
}

public BlockIpEntity ip(String ip) {
    this.setIp(ip);
    return this;
}

// Wrong
public BlockIpEntity setIp(String ip) {
    this.ip = ip;
    return this;
}