Compiling files through Java File using command line

Question

I am looking at ways to compile java files and I know you can compile Java files from the command line using javac Test.java, but is there a way to pass this call to the command line?

Also is there a way to get the command line to compile .tar files in the same way... something like javac -tar Test.tar(passing command from java file).. or what would be the best way to do this?

Sorry im not very good at cmd commands

I'll leave this here as others have already posted correct answers:http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Runtime.html — Colin D, Jul 19 '12 at 17:50
I want to pass these arguments from java to the command prompt — Hip Hip Array, Jul 19 '12 at 17:51

score 5 · Answer 1 · answered Jul 19 '12 at 20:08

5

Java provides an interface to invoke the compilers from programs.

JavaCompiler compiler = ToolProvider
    .getSystemJavaCompiler();

StandardJavaFileManager fileManager = compiler
    .getStandardFileManager(null, null, null);

Iterable<? extends JavaFileObject> compilationUnits = fileManager
    .getJavaFileObjectsFromStrings(Arrays.asList("MyClass.java"));

compiler.getTask(null, fileManager, null, null, null, compilationUnits).call();

fileManager.close();

answered Jul 19 '12 at 20:08

Bertil Chapuis

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I was actually looking at this way of compiling projects and it seems to be compiling but when you try to compile projects that have multiple classes it is not recognizing all the classes (ie. one class that is calling another), it is compiling all the classes but giving out about the import statements for the other classes and anywhere where a method from the other class is called... do you know why this would be happening? – Hip Hip Array Jul 20 '12 at 08:04
You probably have to set the [classpath](http://stackoverflow.com/questions/1563909/how-to-set-classpath-when-i-use-javax-tools-javacompiler-compile-the-source) option. – Bertil Chapuis Jul 20 '12 at 19:45

score 3 · Answer 2 · answered Jul 19 '12 at 17:49

3

Runtime rt = Runtime.getRuntime();
Process pr = rt.exec("javac Test.java");

answered Jul 19 '12 at 17:49

Rob Wagner

4,391
15
24

score 3 · Answer 3 · answered Jul 19 '12 at 17:49

3

You can run system commands from Java using the Runtime class, e.g.

Process p = Runtime.getRuntime().exec("javac Test.java"); 
p.waitFor(); 

BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream())); 
String line; 
while((line = reader.readLine()) != null) { 
    System.out.println(line); 
}

answered Jul 19 '12 at 17:49

ᴇʟᴇvᴀтᴇ

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just playing around with it here, and just wondering can you put this in a method and call it when you want of does it have to be inside the main method? ...'public static void main(String[] args) – Hip Hip Array Jul 19 '12 at 17:58
It can be in a method. `public void execute(String command) throws Exception { ... }` then you can call `execute('java Test.java')` – ᴇʟᴇvᴀтᴇ Jul 19 '12 at 18:05

score 2 · Answer 4 · answered Jul 19 '12 at 17:50

I believe you are asking how to pass a compile command to the command line from java file to compile another java file. This would be done like you would execute any other command to the command line. In my opinion I use process builder for everything, however, this is a great example of when to use .exec() and pass your command line compile command as a string.

score 2 · Answer 5 · answered Jul 19 '12 at 17:55

2

Try this....

Process p = Runtime.getRuntime().exec("javac Test.java");

answered Jul 19 '12 at 17:55

Kumar Vivek Mitra

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Compiling files through Java File using command line

5 Answers5