设置Java编译器合规性级别

我需要在命令行上编译Java程序，我试图将编译器级别设置为较低的（1.6）。 我试过这样但是没有用：

javac -1.6 Hello.java 

Answer 1

使用-source和-target选项：

 javac -target 1.6 -source 1.6 Hello.java 

Answer 2

使用： javac -source 1.6 -target 1.6 Hello.java

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此信息来自运行javac -help ：

 Usage: javac   where possible options include: -g Generate all debugging info -g:none Generate no debugging info -g:{lines,vars,source} Generate only some debugging info -nowarn Generate no warnings -verbose Output messages about what the compiler is doing -deprecation Output source locations where deprecated APIs are used -classpath  Specify where to find user class files and annotation processors -cp  Specify where to find user class files and annotation processors -sourcepath  Specify where to find input source files -bootclasspath  Override location of bootstrap class files -extdirs  Override location of installed extensions -endorseddirs  Override location of endorsed standards path -proc:{none,only} Control whether annotation processing and/or compilation is done. -processor [,,...]Names of the annotation processors to run; bypasses default discovery process -processorpath  Specify where to find annotation processors -d  Specify where to place generated class files -s  Specify where to place generated source files -implicit:{none,class} Specify whether or not to generate class files for implicitly referenced files -encoding  Specify character encoding used by source files -source  Provide source compatibility with specified release -target  Generate class files for specific VM version -version Version information -help Print a synopsis of standard options -Akey[=value] Options to pass to annotation processors -X Print a synopsis of nonstandard options -J Pass  directly to the runtime system 

Answer 3

Java doc说，（搜索交叉编译选项）

By default, classes are compiled against the bootstrap and extension classes of the platform that javac shipped with. But javac also supports cross-compiling, where classes By default, classes are compiled against the bootstrap and extension classes of the platform that javac shipped with. But javac also supports cross-compiling, where classes By default, classes are compiled against the bootstrap and extension classes of the platform that javac shipped with. But javac also supports cross-compiling, where classes platform that javac shipped with. But javac also supports cross-compiling, where classes are compiled against a bootstrap and extension classes of a different Java platform implementation. It is important to use -bootclasspath and -extdirs when cross-compiling; are compiled against a bootstrap and extension classes of a different Java platform implementation. It is important to use -bootclasspath and -extdirs when cross-compiling; implementation. It is important to use -bootclasspath and -extdirs when cross-compiling; see Cross-Compilation Example below.

 -target version 

生成以指定版本的VM为目标的类文件。 类文件将在指定的目标和更高版本上运行，但不会在早期版本的VM上运行。 有效目标是1.1,1.2,1.3,1.4,1.5（也是5），1.6（也是6）和1.7（也是7）。 -target的默认值取决于-source的值：

 If -source is not specified, the value of -target is 1.7 If -source is 1.2, the value of -target is 1.4 If -source is 1.3, the value of -target is 1.4 If -source is 1.5, the value of -target is 1.7 If -source is 1.6, the value of -target is 1.7 For all other values of -source, the value of -target is the value of -source. 

所以，

 javac -target 1.6 -source 1.6 yourJavaProgram.java 

Answer 4

使用以下命令：

 javac -target 1.6 -source 1.6 Hello.java