Dynamic compilation in memory

Question

Hello,
I have used javax.tools.ToolProvider to compile a simple class that comes from a CharSequence object in memory, and it works just fine.
Now, I need to reference another class that comes also from a CharSequence object in memory. Which method in the ForwardingJavaFileManager I should override to make this class available to the main class.
Thank you
The class I need to reference is in class (.class) format not the java source format (.java).
Edited by: Gen.Java on Apr 23, 2013 2:05 AM

Answer 1

CharSequence src = "public class DynaClass {public String toString (){return"hello";}}";Using javax.tools API, this compiles just fine. However,the following does not, complaining that it cannot find the class "another". The bytecode for the class "another" is in memory (not the file system). I just need to make it available to the main class "DynaClass".
CharSequence src = "public class DynaClass {public String toString (){return new another().get();}}";The following is my code:
import java.util.*;
import javax.tools.*;
import java.io.*;
public class DynaCompTest
public static void main(String[] args) throws Exception
JavaCompiler         compiler;
ClassFileManager     fileManager;
List<JavaFileObject> jfiles;
CharSequence         src;
String               fullName;
fullName = "DynaClass";
src      = "public class DynaClass {public String toString (){return"hello";}}";
compiler    = ToolProvider.getSystemJavaCompiler ();
fileManager = new ClassFileManager ( compiler.getStandardFileManager(null, null, null) );
jfiles      = new ArrayList<JavaFileObject>();
jfiles.add  ( new CharSequenceJavaFileObject(fullName,src) );
compiler.getTask ( null, fileManager, null, null, null, jfiles).call ();
import java.net.*;
import javax.tools.*;
public class CharSequenceJavaFileObject extends SimpleJavaFileObject
private CharSequence content;
public       CharSequenceJavaFileObject (
String       className,
CharSequence content                    )
super      ( URI.create("string:///" + className.replace('.', '/')+ Kind.SOURCE.extension), Kind.SOURCE);
this.content = content;
@Override
public CharSequence getCharContent       (
boolean             ignoreEncodingErrors )
return content;
import java.security.*;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.tools.*;
import javax.tools.JavaFileObject.*;
public class ClassFileManager extends ForwardingJavaFileManager<JavaFileManager>
private final Map<String,JavaClassObject> fileObjects;
public                  ClassFileManager (
StandardJavaFileManager standardManager  )
super       ( standardManager );
fileObjects = new HashMap<String,JavaClassObject>();
@Override
public ClassLoader getClassLoader (
Location           location       )
return new ClassLoader() {
           @Override
           protected Class<?> findClass(String name) throws ClassNotFoundException {
                JavaClassObject jco;
                jco      = fileObjects.get(name);
                byte[] b = jco.getByteCode();
                return super.defineClass(name, b, 0, b.length);
@Override
public JavaFileObject getJavaFileForOutput (
Location              location,
String                className,
Kind                  kind,
FileObject            sibling              ) throws IOException
JavaClassObject jco;
jco             = new JavaClassObject(className, kind);
fileObjects.put ( className,jco );
return jco;
import java.net.*;
import java.io.*;
import javax.tools.*;
public class JavaClassObject extends SimpleJavaFileObject
protected final ByteArrayOutputStream bos = new ByteArrayOutputStream();
public JavaClassObject (
String className,
Kind   kind            )
super ( URI.create("string:///" + className.replace('.', '/')+ kind.extension), kind );
public byte[] getByteCode ()
return bos.toByteArray();
@Override
public OutputStream openOutputStream () throws IOException
return bos;
}