What are the uses of null in java

Usage: 1. Initialize the reference type variable to null, indicating that the variable does not currently point to any object; 2. Set the reference type variable to null to release the memory space of the object referenced by the variable. , to help the garbage collector recycle the object; 3. Use null to check whether a reference is empty. You can avoid the occurrence of NullPointerException by judging whether the reference is null; 4. Use null in conditional judgment to judge whether a certain reference is null. Is empty.

#In Java, null means that a reference type variable does not point to any object. You can assign null to any reference type variable, including classes, interfaces, arrays, strings, etc. Null can be used in the following situations:

1. Initialize a reference type variable to null, indicating that the variable does not currently point to any object.

2. Setting a reference type variable to null can release the memory space of the object referenced by the variable and help the garbage collector recycle the object.

3. Use null to check whether a reference is null. You can avoid the occurrence of NullPointerException by judging whether the reference is null.

4. Use null in conditional judgment to judge whether a reference is empty, such as if (myObject == null).

It should be noted that null is a keyword, it is not an object, and it does not belong to any class. When the reference is null, any method of the reference cannot be called, otherwise a NullPointerException will be thrown. Therefore, when using null, you need to pay attention to avoid the occurrence of null pointer exception.

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