CODEWITHSUNDEEP
java
jf328
jf328

Reputation: 7351

java new operator in Array

I find the new operator a bit confusing. My understanding now is that 

new ClassName(...)

is to make an instance and call the Class' constructor. But what does new do when initiating an Array? For example, I feel the two new operators below are different, but can't explain clearly.

Employee[] staff = new Employee[3];
staff[0] = new Employee(...);

Are there any difference?

Thanks.

Upvotes: 1

Views: 545

Answers (3)

jAC
jAC

Reputation: 5324

Employee[] staff = new Employee[3];

Is initializing your array of Employees with 3 "places" which can hold references to your Employee objects.
That means it reserves 3 times the space needed for one object/instance of your Employee class (e.g. 10byte) in the RAM (=> 30 byte).
But your array is initalized with "null". While staff[0] = new Employee(...); is creating a reference to your newly created object of type Employee. arrays

Upvotes: 3

sauv0168
sauv0168

Reputation: 83

When you call the class' constructor, an instance (object) of that class is created. The "new" keyword is what tells the compiler to create an object. An array is a class and you make objects of type Array of SomeClass. You need to use the keyword "new" because you are still creating an object.

Upvotes: 1

Eran
Eran

Reputation: 393866

new Employee[3] creates an array that can hold references to 3 Employee instances. Each of them is initialized to null. staff[0] = new Employee(...); creates an Employee instance and assigns its reference to the first index of the array.

Upvotes: 4

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