12.5

Creation of New Class Instances

EXECUTION

12.5   Creation of New Class Instances

A new class instance is explicitly created when one of the following situations

occurs:

Evaluation of a class instance creation expression ( 15.8) creates a new

instance of the class whose name appears in the expression.

Invocation of the

newInstance

 method ( 20.3.6) of class

Class

 creates a

new instance of the class represented by the

Class

 object for which the

method was invoked.

A new class instance may be implicitly created in the following situations:

Loading of a class or interface that contains a

String

 literal ( 3.10.5) may

create a new

String

 object ( 20.12) to represent that literal. (This might not

occur if the same

String

 has previously been interned ( 3.10.5).)

Execution of a string concatenation operator ( 15.17.1) that is not part of a

constant expression sometimes creates a new

String

 object to represent the

result. String concatenation operators may also create temporary wrapper

objects for a value of a primitive type.

Each of these situations identifies a particular constructor to be called with speci 

fied arguments (possibly none) as part of the class instance creation process.

Whenever a new class instance is created, memory space is allocated for it

with room for all the instance variables declared in the class type and all the

instance variables declared in each superclass of the class type, including all the

instance variables that may be hidden. If there is not sufficient space available to

allocate memory for the object, then creation of the class instance completes

abruptly with an

OutOfMemoryError

. Otherwise, all the instance variables in the

new object, including those declared in superclasses, are initialized to their default

values ( 4.5.4). Just before a reference to the newly created object is returned as

the result, the indicated constructor is processed to initialize the new object using

the following procedure:

1. Assign the arguments for the constructor to newly created parameter variables

for this constructor invocation.

2. If this constructor begins with an explicit constructor invocation of another

constructor in the same class (using

this

), then evaluate the arguments and

process that constructor invocation recursively using these same five steps. If

that constructor invocation completes abruptly, then this procedure completes

abruptly for the same reason; otherwise, continue with step 5.

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