CLASSES

Constructor Modifiers

8.6.3

Constructors are invoked by class instance creation expressions ( 15.8), by

the

newInstance

 method of class

Class

 ( 20.3), by the conversions and concate 

nations caused by the string concatenation operator + ( 15.17.1), and by explicit

constructor invocations from other constructors ( 8.6.5). Constructors are never

invoked by method invocation expressions ( 15.11).

Access to constructors is governed by access modifiers ( 6.6). This is useful,

for example, in preventing instantiation by declaring an inaccessible constructor

( 8.6.8).

Constructor declarations are not members. They are never inherited and there 

fore are not subject to hiding or overriding.

8.6.1   Formal Parameters

The formal parameters of a constructor are identical in structure and behavior to

the formal parameters of a method ( 8.4.1).

8.6.2   Constructor Signature

The signature of a constructor is identical in structure and behavior to the signa 

ture of a method ( 8.4.2).

8.6.3   Constructor Modifiers

ConstructorModifiers:

ConstructorModifier

ConstructorModifiers ConstructorModifier

ConstructorModifier: one of

public protected private

The access modifiers

public

,

protected

, and

private

 are discussed in  6.6.

A compile time error occurs if the same modifier appears more than once in a

constructor declaration, or if a constructor declaration has more than one of the

access modifiers

public

,

protected

, and

private

.

Unlike methods, a constructor cannot be

abstract

,

static

,

final

,

native

,

or

synchronized

. A constructor is not inherited, so there is no need to declare it

final

 and an

abstract

 constructor could never be implemented. A constructor is

always invoked with respect to an object, so it makes no sense for a constructor to

be

static

. There is no practical need for a constructor to be

synchronized

,

because it would lock the object under construction, which is normally not made

available to other threads until all constructors for the object have completed their

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