Kotlin

Unreachable code should be removed, as it serves no purpose. Such code is typically a result of incorrect or unintended control flow in code. It is thus important to correctly structure your code and ensure that all code-paths are reachable and can be executed.

In Kotlin, using const properties is preferred over regular properties for improved performance, efficiency, code clarity, and compile-time safety. const properties are evaluated at compile-time, leading to faster execution and eliminating the need for runtime initialization. const properties also enhance code readability and consistency by

NoSuchElementException is a runtime exception that should be thrown when the next() method is called on an iterator and there are no more elements to iterate over. This exception serves as a signal to the caller that there are no more elements in the collection.

Unreachable catch blocks should be removed, because they serve no useful purpose and can lead to confusing and potentially incorrect behavior in exception handling.

Using the forEach method on ranges has a heavy performance cost. Prefer using simple for loops.

This class/object has a name that does not match agreed-upon naming conventions. Not following naming conventions can lead to confusion among developers and inconsistency in the codebase, which can result in bugs and maintenance issues. It is important to maintain a consistent and easily understandable codebase by following the recommended naming conventions.

Use the safe cast operator (as?) to perform a fallible cast instead of using a condition to check the type before casting. This can simplify operations by directly converting the value to the desired type. The safe cast operator also evaluates to null if the cast fails, reducing verbosity, enforcing null safety, and avoiding an extra if condition. It is considered idiomatic Kotlin to use as? to cast expressions.

When converting primitive types to String, you should avoid creating an object of the respective primitive type first and then using .toString() for converting it to a string. Creating a temporary object is an unnecessary overhead and can incur a performance penalty.

Avoid using is to check the type of exceptions, or as to cast exception types within catch blocks.

Avoid throwing NotImplementedError and using TODO(...) in code.

It is important to ensure that ranges specified in for loops are valid. Ranges that are empty can lead to unexpected behavior.

The hasNext() method in Kotlin's Iterator interface is used to check if there are any more elements in the collection that can be iterated over. This method should have no side-effects and should not modify the underlying collection or iterator state.

Functions which only contain a return statement can be collapsed to an expression body. This shortens the code and makes it more readable.

Collapsing nested if statements into one improves code readability by making it more concise and easier to understand. It simplifies the logic, reduces cyclomatic complexity, and can lead to better performance. Debugging becomes easier, and code maintainability is enhanced. It is important to strike a balance between readability and line length while

In Kotlin, the abstract keyword is redundant when declaring interfaces and their members. Interfaces are implicitly abstract in Kotlin, so there is no need to use the abstract keyword, and the same is true for any members of an interface. Omitting the abstract keyword does not affect the behavior or functionality of an interface, and allows for more concise code.

When a class implements Serializable, it is recommended to also declare a serialVersionUID field within that class. The serialVersionUID serves as a version identifier for the serialized class. It helps to ensure compatibility between the serialized objects and their corresponding class definitions, particularly when performing deserialization.

In Kotlin, it is generally preferred to use a constant variable instead of a function returning a single constant for improved code clarity, performance, and maintainability. Constant variables are more readable, avoid unnecessary runtime overhead, and enable centralized value management. Additionally, they allow potential compiler optimizations

Developers often add TODO or FIXME comments to code that is not complete or needs review. It is a good idea to fix or review such commented code, and remove the comments before considering the code to be production-ready.

In Kotlin, ?. is called the "safe call operator" or "null-safe call operator". It is used to perform a safe access or safe method call on a nullable object. It allows you to execute a method or access a property on an object only if the receiver is not null. If the object is null, the expression will evaluate to null without throwing a NullPointerException.

Do not throw exceptions within finally blocks. Doing so can cause exceptions to be lost.