How NullPointerException can be avoided in Java

A NullPointerException is a common runtime error in Java that occurs when an application attempts to use a null object reference. This can happen when a variable that is supposed to reference an object is not initialized or is set to null, and the code attempts to call a method or access a field on the uninitialized object.

To avoid NullPointerExceptions in your Java code, you can follow these tips:

• Always initialize your object references to a non-null value, such as a default object or an empty collection, before using them in your code. This will ensure that your object references are always pointing to a valid object, and will prevent the NullPointerException from occurring.

List<String> list = new ArrayList<>(); 
// initialize list to an empty ArrayList

• Use the null keyword only when you explicitly want to represent a null value, and avoid using it as a default value for object references. Instead, use a default object or an empty collection, as shown above.

• Use the Optional class to represent optional values, rather than using null directly. The Optional class allows you to safely access the value inside the optional without the risk of a NullPointerException, and provides methods for handling the case when the optional is empty.
  

Optional<String> optional = Optional.ofNullable(str); 
// create an Optional from a potentially null value

• Use the requireNonNull method to validate that an object reference is non-null before using it. This method will throw a NullPointerException if the object is null, which can help you identify and fix null references in your code.

String str = requireNonNull(inputString); 
// throw a NullPointerException if inputString is null

By following these tips, you can avoid NullPointerExceptions and write safer and more reliable Java code.

Happy Coding !!