Shared coding conventions allow teams to collaborate efficiently. This rule checks that all keys match a provided regular expression.

As Java properties files are used in a large variety of ways and by many frameworks, it might sometimes be tricky to enforce a strict key naming convention. However, the default regular expression has been designed to match as closely as possible the following guidelines:

• Only use letters, digits and '.' characters

  bank-account-number=123456   # Noncompliant
  bank_account_owner=John Doe  # Noncompliant
  

• Follow object-oriented programming concept as much as possible. For example, prefer:

  bank.account.number=123456
  bank.account.owner=John Doe
  

  to

  bankAccountNumber=123456
  bankAccountOwner=John Doe
  

• Whenever possible, use lowercase characters. For example, prefer:

  bank.account.number=123456
  bank.account.owner=John Doe
  

  to

  Bank.Account.Number=123456
  Bank.Account.Owner=John Doe
  

  But keep it readable. For example, prefer:

  font.timesNewRoman.size=10
  

  to

  font.timesnewroman.size=10