I am using com.sun.tools.javac.Main.compile()
function to compile java file at run time from my struts projects. But for some files they need some specific jars like axis2. I have the jars but how can i set them to classpath to compile the java file at runtime? I have tried with System.setProperty("java.class.path","jar dir");
but failed to compile.
The following code which uses com.sun.tools.javac.Main
worked for me:
Apple.java
//This class is packaged in a jar named MyJavaCode.jar
import com.xyz.pqr.SomeJavaExamples;
public class Apple {
public static void main(String[] args) {
System.out.println("hello from Apple.main()");
}
}
AClass.java
import com.sun.tools.javac.Main;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
public class AClass {
public static void main(String[] args) {
try {
//Specify classpath using next to -cp
//This looks just like how we specify parameters for javac
String[] optionsAndSources = {
"-g", "-source", "1.5",
"-target", "1.5",
"-cp", ".:/home/JavaCode/MyJavaCode.jar",
"Apple.java"
};
PrintWriter out = new PrintWriter(new FileWriter("./out.txt"));
int status = Main.compile(optionsAndSources, out);
System.out.println("status: " + status);
System.out.println("complete: ");
}catch (Exception e) {}
}
}
Note: To compile this AClass.java
, tools.jar
needs to be in the classpath
, which is not there by default, so you will have to specify it.
If you are using Java 1.6
then you should consider using javax.tools.JavaCompiler
instead, its getTask( ) methods takes an argument options
which can have the classpath
.
For example:
import javax.tools.JavaCompiler;
import javax.tools.ToolProvider;
import javax.tools.JavaFileObject;
public final class AClass {
private static boolean compile(JavaFileObject... source ){
List<String> options = new ArrayList<String>();
// set compiler's classpath to be same as the runtime's
options.addAll(Arrays.asList("-classpath", System.getProperty("java.class.path")));
//Add more options including classpath
final JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
final JavaCompiler.CompilationTask task = compiler.getTask(/*default System.err*/ null,
/*std file manager*/ null,
/*std DiagnosticListener */ null,
/*compiler options*/ options,
/*no annotation*/ null,
Arrays.asList(source));
return task.call();
}
com.sun.tools.javac.Main
is deprecated and undocumented too.
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