Use of Redundant Code

Description

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In the following Java example the code performs some complex math when specific test conditions are met. The math is the same in each case and the equations are repeated within the code. Unfortunately if a future change needs to be made then that change needs to be made in all locations. This opens the door to mistakes being made and the changes not being made in the same way in each instance.

public class Main {

  public static void main(String[] args) {
    double s = 10.0;
    double r = 1.0;
    double pi = 3.14159;
    double surface_area;

    if(r > 0.0) {
      // complex math equations
      surface_area = pi * r * s + pi * Math.pow(r, 2);

    }

    if(r > 1.0) {
      // a complex set of math
      surface_area = pi * r * s + pi * Math.pow(r, 2);

    }

  }


}

It is recommended to place the complex math into its own function and then call that function whenever necessary.

public class Main {

  private double ComplexMath(double r, double s) {
    //complex math equations
    double pi = Math.PI;
    double surface_area = pi * r * s + pi * Math.pow(r, 2);
    return surface_area;

  }


  public static void main(String[] args) {
    double s = 10.0;
    double r = 1.0;
    double surface_area;

    if(r > 0.0) {
      surface_area = ComplexMath(r, s);

    }

    if(r > 1.0) {
      surface_area = ComplexMath(r, s);

    }

  }


}

See Also