Sonar integration

Introduction

This document defines the quality profile the Spring Framework is using for Sonar. It is primarily intended as a revision history of the rules the team has decided to enable (or disable) and why.

Quality profile

The Spring Framework quality profile is based on the standard Sonar Way profile. Note that no findbugs-related rule can be enabled as Java8 support is not there yet.

The Sonar Way brings 114 rules by default.

Disabled rules

These are the rules that we have disabled:

• Right curly brace and next "else", "catch" and "finally" keywords should be located on the same line: our Spring Framework Code Style uses a different style
• Useless parentheses around expressions should be removed to prevent any misunderstanding: we actually use such extra parentheses, especially with the ternary operator
• Tabulation characters should not be used: we do ask our code to use tabs and not spaces
• Throwable and Error classes should not be caught: framework code requires such arrangement in many places
• Generic exceptions Error, RuntimeException, Throwable and Exception should never be thrown: same as above
• Constant names should comply with a naming convention: states that any public static final field is a constant. We address this specifically in constant names
• Loggers should be "private static final" and should share a naming convention: framework code requires non static loggers and some use cases require several loggers in the same class.
• Methods should not be empty: as the framework uses this mechanism for all kinds of extensions points.
• Return an empty array instead of null. as we disagree with this rule the way we use it. null has an additional semantic that we use compared to the one provided by an empty array
• Thread.run() and Runnable.run() should not be called directly as framework code actually requires such call

Under consideration

These are the rules that we may decide to disable eventually:

• Throws declarations should not be redundant: this violation is thrown when an @Override method declares a RuntimeException
• Avoid commented-out lines of code
• Expressions should not be too complex