LoboEvolution/LoboEvolution

Overriding or shadowing a variable declared in an outer scope can strongly impact the readability, and therefore the maintainability, of a piece of code. Further, it could lead maintainers to introduce bugs because they think they're using one variable but are really using another.

Noncompliant Code Example

class Foo {
  public int myField;

  public void doSomething() {
    int myField = 0;
    ...
  }
}

See

• CERT, DCL01-C. - Do not reuse variable names in subscopes
• CERT, DCL51-J. - Do not shadow or obscure identifiers in subscopes

If a private field is declared but not used in the program, it can be considered dead code and should therefore be removed. This will improve maintainability because developers will not wonder what the variable is used for.

Note that this rule does not take reflection into account, which means that issues will be raised on private fields that are only accessed using the reflection API.

Noncompliant Code Example

public class MyClass {
  private int foo = 42;

  public int compute(int a) {
    return a * 42;
  }

}

Compliant Solution

public class MyClass {
  public int compute(int a) {
    return a * 42;
  }
}

Exceptions

The Java serialization runtime associates with each serializable class a version number, called serialVersionUID, which is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization.

A serializable class can declare its own serialVersionUID explicitly by declaring a field named serialVersionUID that must be static, final, and of type long. By definition those serialVersionUID fields should not be reported by this rule:

public class MyClass implements java.io.Serializable {
  private static final long serialVersionUID = 42L;
}

Moreover, this rule doesn't raise any issue on annotated fields.

If a private field is declared but not used in the program, it can be considered dead code and should therefore be removed. This will improve maintainability because developers will not wonder what the variable is used for.

Note that this rule does not take reflection into account, which means that issues will be raised on private fields that are only accessed using the reflection API.

Noncompliant Code Example

public class MyClass {
  private int foo = 42;

  public int compute(int a) {
    return a * 42;
  }

}

Compliant Solution

public class MyClass {
  public int compute(int a) {
    return a * 42;
  }
}

Exceptions

The Java serialization runtime associates with each serializable class a version number, called serialVersionUID, which is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization.

A serializable class can declare its own serialVersionUID explicitly by declaring a field named serialVersionUID that must be static, final, and of type long. By definition those serialVersionUID fields should not be reported by this rule:

public class MyClass implements java.io.Serializable {
  private static final long serialVersionUID = 42L;
}

Moreover, this rule doesn't raise any issue on annotated fields.

If a private field is declared but not used in the program, it can be considered dead code and should therefore be removed. This will improve maintainability because developers will not wonder what the variable is used for.

Note that this rule does not take reflection into account, which means that issues will be raised on private fields that are only accessed using the reflection API.

Noncompliant Code Example

public class MyClass {
  private int foo = 42;

  public int compute(int a) {
    return a * 42;
  }

}

Compliant Solution

public class MyClass {
  public int compute(int a) {
    return a * 42;
  }
}

Exceptions

The Java serialization runtime associates with each serializable class a version number, called serialVersionUID, which is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization.

A serializable class can declare its own serialVersionUID explicitly by declaring a field named serialVersionUID that must be static, final, and of type long. By definition those serialVersionUID fields should not be reported by this rule:

public class MyClass implements java.io.Serializable {
  private static final long serialVersionUID = 42L;
}

Moreover, this rule doesn't raise any issue on annotated fields.