Jiri Tousek PiniCheyni, The 2 ways to create executable jars are explained well here. Add a comment. Complile a Java file to generate a class: javac filename. Paresh Paresh 8 8 silver badges 22 22 bronze badges. Notice that your "filename" is actually a name of a class. The java. Doomjunky Could you explain it, please? Is that bad or good? Should it be named differently? Harshad Holkar Harshad Holkar 5 5 silver badges 14 14 bronze badges. Assuming the file is called "CopyFile.
CopyFile The first line compiles the source code into executable byte code. YakovK YakovK 2 2 silver badges 10 10 bronze badges. Then you can compile your file using command javac A. Eliza Helena Eliza Helena 1 1 silver badge 6 6 bronze badges. Community Bot 1 1 1 silver badge. Within this folder are symbolic links to a handful of java executables but "javac" is NOT one of them so when trying to run "javac" from Windows command line it throws an error. Chris Smith Chris Smith 7 7 silver badges 18 18 bronze badges.
Ashwant Manikoth Ashwant Manikoth 3 3 silver badges 14 14 bronze badges. Horsey Horsey 1 1 silver badge 11 11 bronze badges. Shiba Shiba 44 5 5 bronze badges. This feature has been added in JDK The Overflow Blog.
Stack Gives Back Safety in numbers: crowdsourcing data on nefarious IP addresses. Compiler Design. Computer Organization. Discrete Mathematics. Ethical Hacking. Computer Graphics. Software Engineering.
Web Technology. Cyber Security. C Programming. Control System. Data Mining. Data Warehouse. Javatpoint Services JavaTpoint offers too many high quality services. To do this, follow the following steps- How to install Java? Step 4 Keep clicking on next and don't alter any default setting. You can patch additional content into any module using the --patch-module option.
See [Patching a Module] for more details. To compile a source file, the compiler often needs information about a module or type, but the declaration is not in the source files specified on the command line. This includes classes and interfaces not explicitly mentioned in the source file, but that provide information through inheritance.
For example, when you create a subclass of java. Window , you are also using the ancestor classes of Window : java. Container , java. Component , and java. When compiling code for a module, the compiler also needs to have available the declaration of that module. A successful search may produce a class file, a source file, or both. If both are found, then you can use the -Xprefer option to instruct the compiler which to use; see Extra Options.
If a search finds and uses a source file, then by default javac compiles that source file. This behavior can be altered with -implicit ; see Standard Options. The compiler might not discover the need for some type information until after annotation processing completes.
When the type information is found in a source file and no -implicit option is specified, the compiler gives a warning that the file is being compiled without being subject to annotation processing. To disable the warning, either specify the file on the command line so that it will be subject to annotation processing or use the -implicit option to specify whether or not class files should be generated for such source files. The way that javac locates the declarations of those types depends on whether the reference exists within code for a module or not.
When searching for a source or class file on a path composed of package oriented locations, javac will check each location on the path in turn for the possible presence of the file. The first occurrence of a particular file shadows hides any subsequent occurrences of like-named files. This shadowing does not affect any search for any files with a different name.
This can be convenient when searching for source files, which may be grouped in different locations, such as shared code, platform-specific code and generated code.
It can also be useful when injecting alternate versions of a class file into a package, to debugging or other instrumentation reasons. But, it can also be dangerous, such as when putting incompatible different versions of a library on the class path. Prior to scanning any module paths for any package or type declarations, javac will lazily scan the following paths and locations to determine the modules that will be used in the compilation.
For any module, the first occurrence of the module during the scan completely shadows hides any subsequent appearance of a like-named module. While locating the modules, javac is able to determine the packages exported by the module and to associate with each module a package oriented path for the contents of the module.
For any previously compiled module, this path will typically be a single entry for either a directory or a file that provides an internal directory-like hierarchy, such as a JAR file. Thus, when searching for a type that is in a package that is known to be exported by a module, javac can locate the declaration directly and efficiently.
If the module has been previously compiled, the module declaration is located in a file named module-info. If the module is one of those currently being compiled, the module declaration will be either the file named module-info. When searching for a type that is referenced in code that is not in a module, javac will look in the following places:.
The platform classes or the types in exported packages of the platform modules This is for compiled class files only. Types in exported packages of any modules on the module path, if applicable. This is for compiled class files only.
If both are specified, javac looks for compiled class files on the class path and for source files on the source path. If the class path is specified, but not source path, javac looks for both compiled class files and source files on the class path. If the source file is newer, it will be compiled and will may override any previously compiled version of the file. You can use the -Xprefer option to override the default behavior.
When searching for a type that is referenced in code in a module, javac will examine the declaration of the enclosing module to determine if the type is in a package that is exported from another module that is readable by the enclosing module.
If so, javac will simply and directly go to the definition of that module to find the definition of the required type. Unless the module is another of the modules being compiled, javac will only look for compiled class files files. In other words, javac will not look for source files in platform modules or modules on the module path. If the type being referenced is not in some other readable module, javac will examine the module being compiled to try and find the declaration of the type.
Three different kinds of hierarchy are supported: a package hierarchy , a module hierarchy , and a module source hierarchy. While javac is fairly relaxed about the organization of source code, beyond the expectation that source will be organized in one or package hierarchies, and can generally accomodate organizations prescribed by development environments and build tools, Java tools in general, and javac and the Java launcher in particular, are more stringent regarding the organization of compiled class files, and will be organized in package hierarchies or module hierarchies, as appropriate.
The location of these hierarchies are specified to javac with command-line options, whose names typically end in "path", like --source-path or --class-path. Also as a general rule, path options whose name includes the word module , like --module-path , are used to specify module hierarchies, although some module-related path options allow a package hierarchy to be specified on a per-module basis.
All other path options are used to specify package hierarchies. In a package hierarchy, directories and subdirectories are used to represent the component parts of the package name, with the source file or compiled class file for a type being stored as a file with an extension of.
For example, in a package hierarchy, the source file for a class com. In a module hierarchy, the first level of directories are named for the modules in the hierarchy; within each of those directories the contents of the module are organized in package hierarchies. For example, in a module hierarchy, the compiled class file for a type called com. MyClass in a module called my. The various output directories used by javac the class output directory, the source output directory, and native header output directory will all be organized in a module hierarchy when multiple modules are being compiled.
Although the source for each individual module should always be organized in a package hierarchy, it may be convenient to group those hierarchies into a module source hierarchy. This is similar to a module hierarchy, except that there may be intervening directories between the directory for the module and the directory that is the root of the package hierarchy for the source code of the module.
For example, in a module source hierarchy, the source file for a type called com. The --module-source-path option has two forms: a module-specific form , in which a package path is given for each module containing code to be compiled, and a module-pattern form, in which the source path for each module is specified by a pattern. The module-specific form is generally simpler to use when only a small number of modules are involved; the module-pattern form may be more convenient when the number of modules is large and the modules are organized in a regular manner that can be described by a pattern.
Multiple instances of the --module-source-path option may be given, each one using either the module-pattern form or the module-specific form, subject to the following limitations:. If the module-specific form is used for any module, the associated search path overrides any path that might otherwise have been inferred from the module-pattern form.
The module-specific form allows an explicit search path to be given for any specific module. This form is:. Note: this is similar to the form used for the --patch-module option. The module-pattern form allows a concise specification of the module source path for any number of modules organized in regular manner. The argument is considered to be a series of segments separated by the path separator character ; on Windows, and : otherwise.
If a segment does not contain an asterisk, it is considered to be as though the file separator character and an asterisk are appended. For any module M , the source path for that module is formed from the series of segments obtained by substituting the module name M for the asterisk in each segment. Note : in this context, the asterisk is just used as a special marker, to denote the position in the path of the module name.
You may want to do this to compile alternative implementations of a class to be patched at runtime into a JVM, or to inject additional classes into the module, such as when testing.
The path separator character is ; on Windows, and : otherwise. The paths given for the module must specify the root of a package hierarchy for the contents of the module. The option may be given at most once for any given module. Any content on the path will hide any like-named content later in the path and in the patched module. When patching source code into more than one module, the --module-source-path must also be used, so that the output directory is organized in a module hierarchy, and capable of holding the compiled class files for the modules being compiled.
The API for annotation processors is defined in the javax. Unless annotation processing is disabled with the -proc:none option, the compiler searches for any annotation processors that are available.
The search path can be specified with the -processorpath option. If no path is specified, then the user class path is used.
Processor on the search path. Such files should contain the names of any annotation processors to be used, listed one per line. If class is given, class files will be generated for the source file. The compiler may not discover the need for some type information until after annotation processing is complete. If the type information is found in a source file and no -implicit option is given, the compiler will give a warning that the file is being compiled without being subject to annotation processing.
To disable the warning, either specify the file on the command line so that it will be subject to annotation processing or use the -implicit option to specify whether or not class files should be generated for such source files. To perform a compilation using arguments as you would give on the command line, you can use the following:. This will write any diagnostics to the standard output stream, and return the exit code that javac would give when invoked from the command line.
You can use other methods on the javax. JavaCompiler interface to handle diagnostics, control where files are read from and written to, and so on.
The com. Main class provides two static methods to invoke the compiler from a program:. The args parameter represents any of the command line arguments that would normally be passed to the javac program and are outlined in the above Synopsis section.
Note that all other classes and methods found in a package whose name starts with com. Hello :. The greetings directory is the package directory both for the source file and the class file and is off the current directory. This allows us to use the default user class path.
It also makes it unnecessary to specify a separate destination directory with -d. Since greetings. Hi refers to other classes in the greetings package, the compiler needs to find these other classes. The example above works, because our default user class path happens to be the directory containing the package directory. But suppose we want to recompile this file and not worry about which directory we're in?
If we change greetings. Hi again, to use a banner utility, that utility also needs to be accessible through the user class path. To execute a class in greetings , we need access both to greetings and to the classes it uses. It often makes sense to keep source files and class files in separate directories, especially on large projects.
We use -d to indicate the separate class file destination. Since the source files are not in the user class path, we use -sourcepath to help the compiler find them. To trace automatic compiles, use the -verbose option. The -source 1. The option -target 1. Note that in most cases, the value of the -target option is the value of the -source option; in this example, you can omit the -target option. You must specify the -bootclasspath option to specify the correct version of the bootstrap classes the rt.
If not, the compiler generates a warning:. If you do not specify the correct version of bootstrap classes, the compiler will use the old language rules in this example, it will use version 1.
Skip to Content. All rights reserved.
0コメント