Why can I throw null in Java? [duplicate]
This question already has answers here: Why is “throw null” not creating a compilation error in Java? (4 answers) Closed 3 years ago. … Read more
nullpointerexception
Why should one use Objects.requireNonNull()?
I have noted that many Java 8 methods in Oracle JDK use Objects.requireNonNull(), which internally throws NullPointerException if the given object (argument) is … Read more
NullPointerException in Java with no StackTrace
I’ve had instances of our Java code catch a NullPointerException, but when I try to log the StackTrace (which basically ends up calling … Read more
NullPointerException in Collectors.toMap with null entry values
Collectors.toMap throws a NullPointerException if one of the values is null. I don’t understand this behaviour, maps can contain null pointers as value … Read more
IllegalArgumentException or NullPointerException for a null parameter? [closed]
Closed. This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be … Read more
Why is my Spring @Autowired field null?
Note: This is intended to be a canonical answer for a common problem. I have a Spring @Service class (MileageFeeCalculator) that has an … Read more
Which @NotNull Java annotation should I use?
I’m looking to make my code more readable as well as use tooling like IDE code inspection and/or static code analysis (FindBugs and … Read more
Is null check needed before calling instanceof?
Will null instanceof SomeClass return false or throw a NullPointerException? 8 No, a null check is not needed before using instanceof. The expression … Read more
Avoiding NullPointerException in Java
I use object != null a lot to avoid NullPointerException. What is an alternative to: if (someobject != null) { someobject.doCalc(); } 6 … Read more
What is a NullPointerException, and how do I fix it?
4018 When you declare a reference variable (i.e., an object), you are really creating a pointer to an object. Consider the following code … Read more