Null assignment java

This operation is NPE-safe. NPE means you invoked a method or referred a property on a null reference. That is to say, when your code is like this:. BTW, null reference is a special reference instead of a special value or some compile-time mechanism. Call close only if this. This would have thrown a NullPointerException if the check would have been this.

The result is like a label to a memory address. When result is not null , it's pointing to some memory address where there is an object. So whatever result is currently pointing to does not matter, even if it's null , reassigning result to null will not throw a NPE. The code you posted won't throw a null pointer exception. But after setting the result as null you try to access any method it will throw a null pointer exception. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Assign null to null in Java Ask Question. Asked 6 years, 8 months ago. The nullish coalescing operator is evaluated left to right, it is tested for possible short-circuit evaluation using the following rule: some expression that is neither null nor undefined?? The nullish coalescing operator??

Check Whether a Number is Even or Odd. Check Whether an Alphabet is Vowel or Consonant. Related Topics Java String isEmpty. Java String contains. Java String equalsIgnoreCase. Java String equals. Java String compareTo. Java String compareToIgnoreCase. Java Program to Check if a String is Empty or Null In this program, you'll learn to check if a string is empty or null using a method and the if-else statement in Java.

To understand this example, you should have the knowledge of the following Java programming topics: Java if In Java , a special null value can be assigned to an object reference. NullPointerException is thrown when program attempts to use an object reference that has the null value.

These can be: Invoking a method from a null object. Taking the length of null, as if it were an array. Accessing or modifying the slots of null object, as if it were an array. Throwing null, as if it were a Throwable value. When you try to synchronize over a null object. Why do we need the null value? Null is a special value used in Java. It is mainly used to indicate that no value is assigned to a reference variable.

One application of null is in implementing data structures like linked list and tree. Other applications include Null Object pattern See this for details and Singleton pattern.