Set Java Compiler Compliance Level

Question

I need to compile a Java program on the command line, and I'm trying to set the compiler level to the bottom (1.6). I tried like this, but it did not work:

javac -1.6 Hello.java 

Answer 1

Use the -source and -source options:

 javac -target 1.6 -source 1.6 Hello.java 

Answer 2

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

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This information comes from running javac -help :

 Usage: javac <options> <source files> 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 <path> Specify where to find user class files and annotation processors -cp <path> Specify where to find user class files and annotation processors -sourcepath <path> Specify where to find input source files -bootclasspath <path> Override location of bootstrap class files -extdirs <dirs> Override location of installed extensions -endorseddirs <dirs> Override location of endorsed standards path -proc:{none,only} Control whether annotation processing and/or compilation is done. -processor <class1>[,<class2>,<class3>...]Names of the annotation processors to run; bypasses default discovery process -processorpath <path> Specify where to find annotation processors -d <directory> Specify where to place generated class files -s <directory> Specify where to place generated source files -implicit:{none,class} Specify whether or not to generate class files for implicitly referenced files -encoding <encoding> Specify character encoding used by source files -source <release> Provide source compatibility with specified release -target <release> 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<flag> Pass <flag> directly to the runtime system 

Answer 3

Java doc says (search cross compilation options)

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; implementation. It is important to use -bootclasspath and -extdirs when cross-compiling; see Cross-Compilation Example below.

 -target version 

Generate class files for the specified version of the virtual machine. Class files will run on the specified target and in later versions, but not on earlier versions of the virtual machine. Acceptable goals are 1.1, 1.2, 1.3, 1.4, 1.5 (also 5), 1.6 (also 6) and 1.7 (also 7). The default value for -target depends on the value of -source:

 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. 

So,

 javac -target 1.6 -source 1.6 yourJavaProgram.java 

Answer 4

Use the command below:

 javac -target 1.6 -source 1.6 Hello.java