prowide/prowide-core

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

Looking at the set of methods in a class, including superclass methods, and finding two methods or fields that differ only by capitalization is confusing to users of the class. It is similarly confusing to have a method and a field which differ only in capitalization or a method and a field with exactly the same name and visibility.

In the case of methods, it may have been a mistake on the part of the original developer, who intended to override a superclass method, but instead added a new method with nearly the same name.

Otherwise, this situation simply indicates poor naming. Method names should be action-oriented, and thus contain a verb, which is unlikely in the case where both a method and a member have the same name (with or without capitalization differences). However, renaming a public method could be disruptive to callers. Therefore renaming the member is the recommended action.

Noncompliant Code Example

public class Car{

  public DriveTrain drive;

  public void tearDown(){...}

  public void drive() {...}  // Noncompliant; duplicates field name
}

public class MyCar extends Car{
  public void teardown(){...}  // Noncompliant; not an override. It it really what's intended?

  public void drivefast(){...}

  public void driveFast(){...} //Huh?
}

Compliant Solution

public class Car{

  private DriveTrain drive;

  public void tearDown(){...}

  public void drive() {...}  // field visibility reduced
}

public class MyCar extends Car{
  @Override
  public void tearDown(){...}

  public void drivefast(){...}

  public void driveReallyFast(){...}

}