Why is this an issue?

An empty method is generally considered bad practice and can lead to confusion, readability, and maintenance issues. Empty methods bring no functionality and are misleading to others as they might think the method implementation fulfills a specific and identified requirement.

There are several reasons for a method not to have a body:

• It is an unintentional omission, and should be fixed to prevent an unexpected behavior in production.
• It is not yet, or never will be, supported. In this case an exception should be thrown.
• The method is an intentionally-blank override. In this case a nested comment should explain the reason for the blank override.

How to fix it

Code examples

Noncompliant code example

def shouldNotBeEmpty() = {  // Noncompliant - method is empty
}

def notImplementedYet() = {  // Noncompliant - method is empty
}

def willNeverBeImplemented() = {  // Noncompliant - method is empty
}

def emptyOnPurpose() = {  // Noncompliant - method is empty
}

Compliant solution

def shouldNotBeEmpty() = {
  doSomething()
}

def notImplementedYet() = {
  throw new NotImplementedError()
}

def willNeverBeImplemented() = {
  throw new UnsupportedOperationException()
}

def emptyOnPurpose() = {
  // comment explaining why the method is empty
}