Is this the way Constructor in Java allocates memory?

Question

Default constructor is automatically called after an object is created.

But in Java when we allocate memory using new operator i.e. classname obj = new classna

Answer 1

But in Java when we allocate memory using new operator i.e. classname obj=new classname(); the constructor is automatically invoked before new allocates memory to the class member's.

That is incorrect. The constructor is invoked after memory has been allocated.

@Jon Skeet's answer explains clearly the sequence of events that occur during object creation.

You may be confused by the fact that the constructors may well cause further objects to be allocated; e.g. during the execution of the declaration initializers. But these objects don't occupy memory in the original object; i.e. the object we are constructing.

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If you want a definitive specification of what happens when an object is created, read the Java Language Specification - in particular JLS 12.5.