Names and Identifiers

JLS：https://docs.oracle.com/javase/specs/jls/se7/html/jls-6.html#jls-6.2

Not all identifiers in a program are a part of a name. Identifiers are also used in the following situations:

（1）In declarations (§6.1), where an identifier may occur to specify the name by which the declared entity will be known.

（2）As labels in labeled statements (§14.7) and in break andcontinue statements (§14.15, §14.16) that refer to statement labels.

（3）In field access expressions (§15.11), where an identifier occurs after a "." token to indicate a member of an object that is the value of an expression or the keyword super that appears before the "." token

1、Field Access Expressions

FieldAccess: 
    Primary . Identifier
    super . Identifier
    ClassName . super . Identifier

 

2、Primary Expressions 

Primary:
    PrimaryNoNewArray
    ArrayCreationExpression

PrimaryNoNewArray:
    Literal
    Type . class
    void . class
    this
    ClassName . this
    ( Expression )
    ClassInstanceCreationExpression
    FieldAccess
    MethodInvocation
    ArrayAccess

 

 

3、Method Invocation Expressions

MethodInvocation:
    MethodName ( ArgumentListopt )
    Primary . NonWildTypeArgumentsopt Identifier ( ArgumentListopt )
    super . NonWildTypeArgumentsopt Identifier ( ArgumentListopt )
    ClassName . super . NonWildTypeArgumentsopt Identifier ( ArgumentListopt )
    TypeName . NonWildTypeArguments Identifier ( ArgumentListopt )

3.1、ArgumentList

ArgumentList:
    Expression
    ArgumentList , Expression

　　

4、Class Instance Creation Expressions

ClassInstanceCreationExpression:
    new TypeArgumentsopt TypeDeclSpecifier TypeArgumentsOrDiamondopt
                          ( ArgumentListopt ) ClassBodyopt
    Primary . new TypeArgumentsopt Identifier TypeArgumentsOrDiamondopt
                          ( ArgumentListopt ) ClassBodyopt

TypeArgumentsOrDiamond:
    TypeArguments
    <> 

ArgumentList:
    Expression
    ArgumentList , Expression

　　

　　

　　

 

（4）In some method invocation expressions (§15.12), where an identifier may occur after a "." token and before a "(" token to indicate a method to be invoked for an object that is the value of an expression or the keyword super that appears before the "." token

 

（5）In qualified class instance creation expressions (§15.9), where an identifier occurs immediately to the right of the leftmost new token to indicate a type that must be a member of the compile-time type of the primary expression preceding the "." preceding the leftmost new token.