java代码文法产生语言

Java代码的文法可以用BNF（巴克斯-诺尔范式）表示，如下所示：

<compilationUnit> ::= [<packageDeclaration>] [<importDeclaration>] {<typeDeclaration>}

<packageDeclaration> ::= "package" <qualifiedName> ";"

<importDeclaration> ::= "import" ["static"] <qualifiedName> ["." "*"] ";"

<typeDeclaration> ::= <classDeclaration> | <interfaceDeclaration>

<classDeclaration> ::= {<modifier>} "class" <identifier> [<typeParameters>] [<superclass>] [<superinterfaces>] <classBody>

<interfaceDeclaration> ::= {<modifier>} "interface" <identifier> [<typeParameters>] [<extendsInterfaces>] <interfaceBody>

<modifier> ::= "public" | "protected" | "private" | "static" | "abstract" | "final" | "native" | "synchronized" | "transient" | "volatile" | "strictfp"

<typeParameters> ::= "<" <typeParameterList> ">"

<typeParameterList> ::= <typeParameter> {"," <typeParameter>}

<typeParameter> ::= <identifier> [<extendsBound>]

<extendsBound> ::= "extends" <type> [<additionalBound> {"," <additionalBound>}]

<additionalBound> ::= "extends" <type>

<superclass> ::= "extends" <classType>

<superinterfaces> ::= "implements" <interfaceTypeList>

<classBody> ::= "{" {<classBodyDeclaration>} "}"

<classBodyDeclaration> ::= <classMemberDeclaration> | <staticInitializer> | <constructorDeclaration>

<classMemberDeclaration> ::= <fieldDeclaration> | <methodDeclaration> | <classDeclaration> | <interfaceDeclaration> | <enumDeclaration>

<staticInitializer> ::= "static" <block>

<constructorDeclaration> ::= {<modifier>} <constructorDeclarator> <throws> <constructorBody>

<constructorDeclarator> ::= <identifier> "(" [<formalParameterList>] ")"

<formalParameterList> ::= <formalParameter> {"," <formalParameter>}

<formalParameter> ::= {<annotation>} [<final>] <type> <variableDeclaratorId>

<variableDeclaratorId> ::= <identifier> [<dims>]

<dims> ::= "[" "]"

<methodDeclaration> ::= {<modifier>} <type> <methodDeclarator> <throws> [<methodBody> | <nativeMethodBody>]

<methodDeclarator> ::= <identifier> "(" [<formalParameterList>] ")"

<methodBody> ::= <block>

<nativeMethodBody> ::= "native" ";"

<fieldDeclaration> ::= {<modifier>} <type> <variableDeclarators> ";"

<variableDeclarators> ::= <variableDeclarator> {"," <variableDeclarator>}

<variableDeclarator> ::= <variableDeclaratorId> ["=" <variableInitializer>]

<variableInitializer> ::= <expression> | <arrayInitializer>

<arrayInitializer> ::= "{" [<variableInitializer> {"," <variableInitializer>}] [","] "}"

<block> ::= "{" {<blockStatement>} "}"

<blockStatement> ::= <localVariableDeclarationStatement> | <statement>

<localVariableDeclarationStatement> ::= <type> <variableDeclarators> ";"

<statement> ::= <expressionStatement> | <declarationStatement> | <ifStatement> | <switchStatement> | <whileStatement> | <doStatement> | <forStatement> | <breakStatement> | <continueStatement> | <returnStatement> | <throwStatement> | <tryStatement>

<expressionStatement> ::= [<expression>] ";"

<declarationStatement> ::= <localVariableDeclarationStatement>

<ifStatement> ::= "if" "(" <expression> ")" <statement> ["else" <statement>]

<switchStatement> ::= "switch" "(" <expression> ")" "{" {<switchBlockStatementGroup>} "}"

<switchBlockStatementGroup> ::= <switchLabels> <blockStatements>

<switchLabels> ::= <switchLabel> {<switchLabel>}

<switchLabel> ::= "case" <constantExpression> ":" | "default" ":"

<blockStatements> ::= {<blockStatement>}

<whileStatement> ::= "while" "(" <expression> ")" <statement>

<doStatement> ::= "do" <statement> "while" "(" <expression> ")" ";"

<forStatement> ::= "for" "(" [<forControl>] ")" <statement>

<forControl> ::= <enhancedForControl> | <forInit> ";" [<expression>] ";" [<forUpdate>]

<enhancedForControl> ::= <type> <variableDeclaratorId> ":" <expression>

<forInit> ::= <localVariableDeclarationStatement> | [<expressionList>]

<forUpdate> ::= <expressionList>

<expressionList> ::= <expression> {"," <expression>}

<breakStatement> ::= "break" [<identifier>] ";"

<continueStatement> ::= "continue" [<identifier>] ";"

<returnStatement> ::= "return" [<expression>] ";"

<throwStatement> ::= "throw" <expression> ";"

<tryStatement> ::= "try" <block> <catches> [<finally>] | "try" <resourceSpecification> <block> [<catches>] [<finally>]

<resourceSpecification> ::= "(" {<resource>} [","] ")"

<resource> ::= <variableModifiers> <classType> <variableDeclaratorId> "=" <expression>

<catches> ::= {<catchClause>}

<catchClause> ::= "catch" "(" <catchFormalParameter> ")" <block>

<catchFormalParameter> ::= [<final>] <catchType> <variableDeclaratorId>

<catchType> ::= <qualifiedName> { "|" <qualifiedName>}

<finally> ::= "finally" <block>

<annotation> ::= "@" <qualifiedName> [<elementValuePairs>] | "@" <qualifiedName> "(" [<elementValuePairs>] ")"

<elementValuePairs> ::= <elementValuePair> {"," <elementValuePair>}

<elementValuePair> ::= <identifier> "=" <elementValue>

<elementValue> ::= <expression> | <annotation> | <elementValueArrayInitializer>

<elementValueArrayInitializer> ::= "{" {<elementValue>} [","] "}"

这个文法描述了Java代码的语法结构，可以用于编写Java编译器。