programatically compile

[Amir Iqbal]

would any one please tell me that if i want to compile "abc.txt"(in which i have written simple java code) from my java programe(say TestClass) how can i do this??? if someone knows the code please do paste in reply......i am waiting for your response......

regards:
Amir Iqbal

[Ulf Dittmer]

Can you store the code in .java file on disk? If so, you can use the javac compiler internally, somewhat like this:

static int com.sun.tools.javac.Main.compile(String[], PrintWriter)

The first parameter is an array of absolute paths of Java source files, the second is where error messages should go, so you might use "new PrintWriter(System.err)" for it. It returns 0 if compilation worked fine, some other int if not.

If it all needs to be in memory then it gets a bit trickier. I described how it can work in this recent article.

Another approach would be to drive javac using Runtime.exec. Which method is best depends on what you intend to do with the resulting class.
[ November 10, 2007: Message edited by: Ulf Dittmer ]

[Rob Spoor]

You can also check out these examples from java2s.com. Please note that you have to run it from the java.exe from the JDK bin folder, otherwise you'll get a null Java Compiler object.

[Amir Iqbal]

thanks alot my frndz Ulf and Rob and everyone who paid attention.
thank you very much.

[Jesper de Jong]

Originally posted by Ulf Dittmer:
Can you store the code in .java file on disk? If so, you can use the javac compiler internally, somewhat like this:

static int com.sun.tools.javac.Main.compile(String[], PrintWriter)

Note that if you do this, you are using an internal Sun package, that you're not really supposed to use. See this: Why Developers Should Not Write Programs That Call 'sun' Packages.

Since Java 6, there is an official API to call the Java compiler from your program. It is in the package javax.tools. Lookup the API documentation for that package.