https://stackoverflow.com › questions › 411447

It is almost always possible to design your code such that a null value is never returned from your APIs during "normal" flow of execution. (For example, check foo.contains(obj) rather then calling foo.get(obj) and having a separate branch for null. Or, use the Null object pattern.

https://stackoverflow.com › questions › 17302256

Before calling a function of an object, I need to check if the object is null, to avoid throwing a NullPointerException. What is the best way to go about this? I've considered these methods. Which one is the best programming practice for Java? // Method 1 if (foo != null) { if (foo.bar()) { etc... } } // Method 2 if (foo != null ? foo.bar ...

https://www.baeldung.com › java-avoid-null-check

Learn several strategies for avoiding the all-too-familiar boilerplate conditional statements to check for null values in Java.

https://docs.oracle.com › javase › 8 › docs › api › java › util › Objects.html

Checks that the specified object reference is not null. This method is designed primarily for doing parameter validation in methods and constructors, as demonstrated below: public Foo(Bar bar) { this.bar = Objects.requireNonNull(bar); }

https://www.baeldung.com › java-notnull-method-parameter

In this article, we learned how to use the @NotNull annotation on a method parameter in a standard Java application. We also learned how to use Spring Boot’s @Validated annotation to simplify our Spring Bean method parameter validation while also noting its limitations.

https://www.baeldung.com › java-check-all-variables-object-null

The simplest way is using a sequence of if statements to check field by field if they are null or not and, in the end, return a combination of their results. Let’s define the allNull() method inside the Car class:

https://betterprogramming.pub › checking-for-nulls-in-java-minimize-using-if-else-edae...

Optional.ofNullable () Returns an Optional describing the given value, if non-null, otherwise returns an empty Optional.¹. The returned value from this method will never be null. If it is null, the returned value will be Optional.empty(). This way, if the result of this method is used somewhere else, there will be no chance of getting a NPE.

https://docs.oracle.com › javase › 8 › docs › api › java › lang › NullPointerException.html

Thrown when an application attempts to use null in a case where an object is required. These include: Calling the instance method of a null object. Accessing or modifying the field of a null object. Taking the length of null as if it were an array. Accessing or modifying the slots of null as if it were an array.

https://medium.com › swlh › null-checking-done-right-with-optionals-78003c9329a7

Fortunately, you can reduce your null-checking boilerplate code using the Optional class for most of the cases. The Optional API was first introduced as part of the Java Development Kit 8, and...

https://stackoverflow.com › questions › 8347163

A blank declaration (one where no value is assigned) is a great way to avoid null checks; the compiler will not allow the variable to be read until a value is assigned, so you can't check it for null or attempt to de-reference it.