https://stackoverflow.com › questions › 411447

For Java, one can use the Javadoc description of a method to document the meaning of the returned value, including whether it can be null. As has been mentioned, annotations may also provide assistance here.

https://stackoverflow.com › questions › 2250031

You could potentially write a helper method which returned an empty sequence if you passed in null: public static <T> Iterable<T> emptyIfNull(Iterable<T> iterable) { return iterable == null ? Collections.<T>emptyList() : iterable; } Then use: for (Object object : emptyIfNull(someList)) { }

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

java.lang.NullPointerException. All Implemented Interfaces: Serializable. public class NullPointerException . extends RuntimeException. 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.

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

If a value is present, apply the provided mapping function to it, and if the result is non-null, return an Optional describing the result. Otherwise return an empty Optional.

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

The methods of this class all throw a NullPointerException if the collections or class objects provided to them are null. The documentation for the polymorphic algorithms contained in this class generally includes a brief description of the implementation.

https://softwareengineering.stackexchange.com › questions › 51076

The javadoc for a method that allows a null parameter or returns a null value must clearly document this, and explain what the null means. Rule #2: An API method should not be specified as accepting or returning null unless there is a good reason to do so.

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-avoid-null-check

In this tutorial, we’ll take a look at the need to check for null in Java and various alternatives that help us to avoid null checks in our code. Further reading: Using NullAway to Avoid NullPointerExceptions

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

These utilities include null-safe or null-tolerant methods for computing the hash code of an object, returning a string for an object, and comparing two objects.

https://blog.joda.org › 2012 › 11 › javadoc-coding-standards.html

The two agree in most places, however these guidelines are more explicit about HTML tags, two spaces in @param and null-specification, and differ in line lengths and sentence layout. Each of the guidelines below consists of a short description of the rule and an explanation, which may include an example: Write Javadoc to be read as source code.