8.1

Class Declaration

CLASSES

A field may be declared

final

 ( 8.3.1.2), in which case it cannot be assigned to

except as part of its declaration. Any field declaration may include an initializer;

the declaration of a

final

 field must include an initializer.

Method declarations ( 8.4) describe code that may be invoked by method

invocation expressions ( 15.11). A class method is invoked relative to the class

type; an instance method is invoked with respect to some particular object that is

an instance of the class type. A method whose declaration does not indicate how it

is implemented must be declared

abstract

. A method may be declared

final

( 8.4.3.3), in which case it cannot be hidden or overridden. A method may be

implemented by platform dependent

native

 code ( 8.4.3.4). A

synchronized

method ( 8.4.3.5) automatically locks an object before executing its body and

automatically unlocks the object on return, as if by use of a

synchronized

 state 

ment ( 14.17), thus allowing its activities to be synchronized with those of other

threads ( 17).

Method names may be overloaded ( 8.4.7).

Static initializers ( 8.5) are blocks of executable code that may be used to

help initialize a class when it is first loaded ( 12.4).

Constructors ( 8.6) are similar to methods, but cannot be invoked directly by

a method call; they are used to initialize new class instances. Like methods, they

may be overloaded ( 8.6.6).

8.1   Class Declaration

A

class declaration

 specifies a new reference type:

ClassDeclaration:

ClassModifiers

opt

 class

Identifier Super

opt

Interfaces

opt

ClassBody

If a class is declared in a named package ( 7.4.1) with fully qualified name

P

( 6.7), then the class has the fully qualified name

P.

Identifier

. If the class is in an

unnamed package ( 7.4.2), then the class has the fully qualified name

Identifier

.

In the example:

class Point { int x, y; }

the class

Point

 is declared in a compilation unit with no

package

 statement, and

thus

Point

 is its fully qualified name, whereas in the example:

package vista;

class Point { int x, y; }

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