Using com.sun.tools.javac.Main() for compiling

[Jesper Sahner]

Hi!

I want to create a dynamic class "on the fly". For this I use:

String[] s = {"Myclass.java"};
(new com.sun.tools.javac.Main()).compile(s);

This works fine. The code reads the .java-file and creates the
..class-file. No problem.

Now I wonder if the same thing can be done without using external
files. The source-code for the .java-file could be held in e.g. a
String-object, and the byte-code as a result of the compilation could
be parsed to a ClassLoader-object.

However I don't how to do this, but I think it must be possible.

Any ideas?

Regards,
Jesper

 

[Fahd Shariff]

You could create a Temporary file which you can delete later on.

Or you can look at javac's source code and see if there is any other
method that might do what you are looking for...

 

[Andrew Thompson]

Or you can look at javac's source code ...

Where exactly? It is not included in the distributed src.zip.

 

[hiwa]

You could create a Temporary file which you can delete later on.

Or you can look at javac's source code and see if there is any other
method that might do what you are looking for...

Using temporary file is good because no hack is needed. We can't
access javac's input stream by a standard way.

 

[ExGuardianReader]

Using temporary file is good because no hack is needed. We can't
access javac's input stream by a standard way.

I've looked at the source code, and there seems to be no other access to
the compiler other than through a file.

This seems very poor design with InputStreams available. We should to be
able to provide an InputStream of Java source code to a compiler method
to generate new bytecode.

Generating skeleton server classes would be much neater if you could do
this.

 

[Jesper Sahner]

How do you access the source code? You only have the byte-code as far as I know.

Regards,
Jesper

 

[ExGuardianReader]

How do you access the source code? You only have the byte-code as far as I know.

Regards,
Jesper

There are quite a few Java decompilers around, do a google.

I use DJ: http://members.fortunecity.com/neshkov/

 

[Jesper Sahner]

I've looked at the source code, and there seems to be no other access to
the compiler other than through a file.

This seems very poor design with InputStreams available. We should to be
able to provide an InputStream of Java source code to a compiler method
to generate new bytecode.

Agreed! There are some byte-code generators around, e.g. BCEL, ASM,
Soot etc., but for this it is "overkill".

Generating skeleton server classes would be much neater if you could do
this.

Could you explain this in more details or add some keywords?

Regards,
Jesper