How to check if object is null or not other than == null
I want to create a method that will check if an instance of a class is null or not.
It's just that I know I can use it == null
, but I want to know if there is another way that can be implemented to check if an instance is null or not?
I have an instance of a class 70-80
. and this whole class extends the same class BaseEntity
.
during declaration, I declare each instance, for example:
Entity1 instance1 = null;
so I defined everything 70 class instances
.
when they are used I initialize them with new. but at the end of my main one Entity Processor
, I have to store the data of each Entity it is initialized, so for that I need to check if the instance is null or not?
All Entities extend
the same class BaseEntity
, so I made the following method.
I only know one method:
public boolean checkIfEntityNull(BaseEntity entity){
return entity != null ? true : false;
}
if it returns true
then I'll call it save method of repository to save data in DB
, otherwise it won't call the save method.
So any advice on this guys.
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The easiest way to check: entity == null
. There is no shorter way to do this.
Note that there is a method in the standard lib:
And one more, opposite to the above:
And there is another way that can be used to ensure that the value is not null
, it throws out NullPointerException
otherwise:
T Objects.requireNonNull (T obj);
Note. Class Objects was added in Java 7, but isNull()
and nonNull()
were added only in Java 8.
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