how convert a particular .java to .class with coding?

Question

I have an issue for my application.

I want to convert selected .java file to .class file at same path.

for that i am using:

   File directoryPath = new File(".");
    String command ="cmd.exe /C "+ directoryPath.getCanonicalPath()+"\\javac UpsOfferDataDaily.java"; 
                Runtime.getRuntime().exec(command);

any thing strange with that??

It Can't execute my command successfully.

directory path will be same as the .java is situated.

what should i do...

Thanks in advance:

What doesn directoryPath contains? Are you sure it's the path to javac, and not to your .java to compile? — foch, Feb 18 '12 at 09:24
Print the first line to your console to see the output of your command. Then you can see if it works as expected. And you can try to run it directly in a cmd — Maarten Kesselaers, Feb 18 '12 at 09:25
Use Process to read from the error stream....u ll atleast cum to kn wat the error is.... — Shashank Kadne, Feb 18 '12 at 09:35
@ShashankKadne i want to do .java to .class file but i have no idea how to do with code. so if you have any idea then tell me. — Siten, Feb 18 '12 at 09:37

Shashank Kadne · Accepted Answer · 2012-02-18T09:54:10.987

2

Try this....javac is already in my path. So i jus gave the filename. Errors will be shown by the error stream, if any...It worked for me!!!

String command ="cmd.exe /C "+ "javac C:\\student\\workspace\\javaproject\\Testing\\src\\TestCalculator.java"; 
        Process p = Runtime.getRuntime().exec(command);
        InputStream i = p.getErrorStream();
        int c;
        while((c=i.read())!=-1)
            System.out.print((char)c);

edited Feb 18 '12 at 09:54

answered Feb 18 '12 at 09:46

Shashank Kadne

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I am getting error like "javac' is not recognized as an internal or external command,operable program or batch file."How to set the path bydefault in cmd when this command excute. – Siten Feb 18 '12 at 09:54
You set it externally...set the environmental variable "path"...right computer > Properties >Advanced tab > Environmental variables – Shashank Kadne Feb 18 '12 at 09:57
No...you still got the error??...open cmd from outside...and type javac and see if it recognizes the command..... – Shashank Kadne Feb 18 '12 at 10:05
i set path environment till/bin. java command is working but javac is not working and after that i manually set the java path till /bin then javac command is running. after that i run your code it give same error. i am hang... – Siten Feb 18 '12 at 10:12
No manual setting wud be limited to that prompt itself....did you make sure javac file exist inside your bin....if java is working directly den javac shud work too... – Shashank Kadne Feb 18 '12 at 10:15

score 2 · Answer 2 · answered Feb 18 '12 at 09:50

2

You could use the built-in api; javax.tool.JavaCompiler.

http://docs.oracle.com/javase/7/docs/api/javax/tools/JavaCompiler.html

http://www.javabeat.net/articles/73-the-java-60-compiler-api-1.html

answered Feb 18 '12 at 09:50

KarlP

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how convert a particular .java to .class with coding?

2 Answers2