sgammon/GUST

Cognitive Complexity is a measure of how hard the control flow of a method is to understand. Methods with high Cognitive Complexity will be difficult to maintain.

See

• Cognitive Complexity

Cognitive Complexity is a measure of how hard the control flow of a method is to understand. Methods with high Cognitive Complexity will be difficult to maintain.

See

• Cognitive Complexity

Using such generic exceptions as Error, RuntimeException, Throwable, and Exception prevents calling methods from handling true, system-generated exceptions differently than application-generated errors.

Noncompliant Code Example

public void foo(String bar) throws Throwable {  // Noncompliant
  throw new RuntimeException("My Message");     // Noncompliant
}

Compliant Solution

public void foo(String bar) {
  throw new MyOwnRuntimeException("My Message");
}

Exceptions

Generic exceptions in the signatures of overriding methods are ignored, because overriding method has to follow signature of the throw declaration in the superclass. The issue will be raised on superclass declaration of the method (or won't be raised at all if superclass is not part of the analysis).

@Override
public void myMethod() throws Exception {...}

Generic exceptions are also ignored in the signatures of methods that make calls to methods that throw generic exceptions.

public void myOtherMethod throws Exception {
  doTheThing();  // this method throws Exception
}

See

• MITRE, CWE-397 - Declaration of Throws for Generic Exception
• CERT, ERR07-J. - Do not throw RuntimeException, Exception, or Throwable

Utility classes, which are collections of static members, are not meant to be instantiated. Even abstract utility classes, which can be extended, should not have public constructors.

Java adds an implicit public constructor to every class which does not define at least one explicitly. Hence, at least one non-public constructor should be defined.

Noncompliant Code Example

class StringUtils { // Noncompliant

  public static String concatenate(String s1, String s2) {
    return s1 + s2;
  }

}

Compliant Solution

class StringUtils { // Compliant

  private StringUtils() {
    throw new IllegalStateException("Utility class");
  }

  public static String concatenate(String s1, String s2) {
    return s1 + s2;
  }

}

Exceptions

When class contains public static void main(String[] args) method it is not considered as utility class and will be ignored by this rule.

Checks that the order of modifiers conforms to the suggestions inthe JavaLanguage specification, § 8.1.1, 8.3.1, 8.4.3 and9.4. The correct order is:

1. public
2. protected
3. private
4. abstract
5. default
6. static
7. final
8. transient
9. volatile
10. synchronized
11. native
12. strictfp

In additional, modifiers are checked to ensure all annotations aredeclared before all other modifiers.

Rationale: Code is easier to read if everybody follows a standard.

ATTENTION: We skiptype annotations from validation.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks that the order of modifiers conforms to the suggestions inthe JavaLanguage specification, § 8.1.1, 8.3.1, 8.4.3 and9.4. The correct order is:

1. public
2. protected
3. private
4. abstract
5. default
6. static
7. final
8. transient
9. volatile
10. synchronized
11. native
12. strictfp

In additional, modifiers are checked to ensure all annotations aredeclared before all other modifiers.

Rationale: Code is easier to read if everybody follows a standard.

ATTENTION: We skiptype annotations from validation.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

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

Noncompliant Code Example

With the default regular expression ^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$:

public class MyClass {
  public static final int first = 1;
}

public enum MyEnum {
  first;
}

Compliant Solution

public class MyClass {
  public static final int FIRST = 1;
}

public enum MyEnum {
  FIRST;
}