Top "Nullpointerexception" questions

The Java exception thrown when an application attempts to use null in a case where an object is required.

What is a NullPointerException, and how do I fix it?

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine …

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How to avoid null checking in Java?

I use object != null a lot to avoid NullPointerException. Is there a good alternative to this? For example I often …

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How to solve java.lang.NullPointerException error?

When I run my Java program, it gives me an error on this line compiler.getTask(null, null, new DiagnosticCollector&…

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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) …

java spring null nullpointerexception autowired
java.lang.NullPointerException: Attempt to invoke virtual method on a null object reference

I am trying to save player's name in shared preference and make it display in another activity by getting it …

java android nullpointerexception
Android - How To Override the "Back" button so it doesn't Finish() my Activity?

I currently have an Activity that when it gets displayed a Notification will also get displayed in the Notification bar. …

android android-activity nullpointerexception back-button onkeypress
Converting a Date object to a calendar object

So I get a date attribute from an incoming object in the form: Tue May 24 05:05:16 EDT 2011 I am writing a …

java date calendar nullpointerexception
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 …

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Is null check needed before calling instanceof?

Will null instanceof SomeClass return false or throw a NullPointerException?

java nullpointerexception null
Filter values only if not null using lambda in Java8

I have a list of objects say car. I want to filter this list based on some parameter using Java 8. …

java lambda nullpointerexception null java-8