GoogleMethodName

Since Checkstyle 13.3.0

Description

Checks that method names conform to the Google Java Style Guide for method naming.

This check enforces Google's specific method naming requirements:

Method names must start with a lowercase letter and use uppercase letters for word boundaries.
Underscores may appear in JUnit test method names to separate logical components.
Underscores may be used to separate adjacent numbers (e.g., version numbers like guava33_4_5), but NOT between letters and digits.

Examples

To configure the check:


<module name="Checker">
  <module name="TreeWalker">
    <module name="GoogleMethodName"/>
  </module>
</module>

Code Example:


class Example1 {
  public void fooBar() {}
  public void guava33_4_5() {}
  public void parseXml() {}

  public void Foo() {}
  // violation above, 'Method name 'Foo' must start with a lowercase letter'

  public void gradle_9_5_1() {}
  // violation above, 'underscores only allowed between adjacent digits.'

  @Test
  public void login() {}

  @Test
  public void jdk17_0_1() {}

  @Test
  public void testLogin_failsGracefully12() {}

  @Test
  public void transferMoney_deductsFromSource() {}

  @Test
  public void login_fails() {}
  // violation above, 'contain at least one uppercase letter for multi-segment names'

  @Test
  public void test_foo_1() {}
  // violation above, 'underscore only allowed between letters or between digits.'

  @Test
  public void f$bar() {}
  // violation above, 'contain only letters, digits, or underscores.'

  @Test
  public void test_Foo() {}
  // violation above, 'Each segment must start lowercase'
}

Example of Usage

Google Style

Violation Messages

All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.

Package

com.puppycrawl.tools.checkstyle.checks.naming

Parent Module

TreeWalker