Thread Subject: Debugging java class called from Matlab

Hello all,

I wish to debug a Java class that I call from Matlab. Is
there any way to connect Eclipse (or something else) to set
debuggable breakpoints in my Java code?

(simple system.out.println works of course, but I need a
more heavy-duty debugger)

Thanks,
Yair Altman

"Yair Altman" <altmanyDEL@gmailDEL.comDEL> wrote in message
<fb1gnk$5o4$1@fred.mathworks.com>...
> Hello all,
>
> I wish to debug a Java class that I call from Matlab. Is
> there any way to connect Eclipse (or something else) to set
> debuggable breakpoints in my Java code?
>
> (simple system.out.println works of course, but I need a
> more heavy-duty debugger)
>
> Thanks,
> Yair Altman

Hi Yair,

I just figured out how to do it for MATLAB 7R14 (should work
for later versions) and Eclipse (I'm using JBuilder 2007,
which is Eclipse 3.2.2). Here is how:

1) Create a Eclipse project (you must use JDK 1.5 or above)
to include the source code of your java classes, remember
the directory where you put the output classes when you
define your project.

2) Add the following flags in java.opts in directory
%MATLAB_ROO%\bin\arch.

-Xdebug
-Xrunjdwp:transport=dt_socket,address=1044,server=y,suspend=n

3) In your eclipse project, define a debug configuration.
For me, I've to add a "Remote Java Application"
configuration. In the "Connection Type" field, use "Standard
(Socket Attach)". Then use "localhost" for field "Host" and
"1044" for "Port".

4) Then launch MATLAB, make sure you add the directory of
the output classes from step 1 into MATLAB's javaclasspath.
You can use either static or dynamic classpath here.

5) Then debug the "Remote Java Application" on the Eclipse
side, put a break point in your java code and instantiate or
execute your java code from within MATLAB. You should see
the breakpoint popping up when MATLAB calls java.

Have fun!

I just found out that port 1044 is very popular (used by
many software) which causes MATLAB not to launch if there is
any other process is using the port. So changing it to
something else would be a good idea.

"Ed Yu" <ekyu88@hotmail.com> wrote in message
<fqrpem$r2s$1@fred.mathworks.com>...
> I just found out that port 1044 is very popular (used by
> many software) which causes MATLAB not to launch if there is
> any other process is using the port. So changing it to
> something else would be a good idea.

Also a good idea to use the follow flag to disable JIT compiler:

-Djava.compiler=NONE

"Ed Yu" <ekyu88@hotmail.com> wrote in message <fiptu4
$l3b$1@fred.mathworks.com>...
> "Yair Altman" <altmanyDEL@gmailDEL.comDEL> wrote in
message
> <fb1gnk$5o4$1@fred.mathworks.com>...
> > Hello all,
> >
> > I wish to debug a Java class that I call from Matlab. Is
> > there any way to connect Eclipse (or something else) to
set
> > debuggable breakpoints in my Java code?
> >
> > (simple system.out.println works of course, but I need a
> > more heavy-duty debugger)
> >
> > Thanks,
> > Yair Altman
>
> Hi Yair,
>
> I just figured out how to do it for MATLAB 7R14 (should
work
> for later versions) and Eclipse (I'm using JBuilder 2007,
> which is Eclipse 3.2.2). Here is how:
>
> 1) Create a Eclipse project (you must use JDK 1.5 or
above)
> to include the source code of your java classes, remember
> the directory where you put the output classes when you
> define your project.
>
> 2) Add the following flags in java.opts in directory
> %MATLAB_ROO%\bin\arch.
>
> -Xdebug
> -
Xrunjdwp:transport=dt_socket,address=1044,server=y,suspend=n
>
> 3) In your eclipse project, define a debug configuration.
> For me, I've to add a "Remote Java Application"
> configuration. In the "Connection Type" field,
use "Standard
> (Socket Attach)". Then use "localhost" for field "Host"
and
> "1044" for "Port".
>
> 4) Then launch MATLAB, make sure you add the directory of
> the output classes from step 1 into MATLAB's
javaclasspath.
> You can use either static or dynamic classpath here.
>
> 5) Then debug the "Remote Java Application" on the Eclipse
> side, put a break point in your java code and instantiate
or
> execute your java code from within MATLAB. You should see
> the breakpoint popping up when MATLAB calls java.
>
> Have fun!

Works quite well, thanks! Also, helps to remember to
compile with -g flag as usual, to generate the debugging
info. (javac -g YourBuggyCode.java)

Hi,

Please help me in getting the second point mentioned above. I am not able to find the path %MATLAB_ROO%\bin\arch.
Please explain me more....

Thanks in advance

This seems like a good idea, but it didn't work for me. I believe I followed the instructions, but when I run the launcher in Eclipse, I get a dialog saying:

Failure to connect to remote VM. Connection refused.
Connection refused: connect

This happens whether Matlab is started before the launcher or after.

I made the file java.opts in C:\Program Files\Matlab\2007a\bin\win32.

Possible reasons:

1. I tried putting the opts on one line or on multiple lines as in the forum message. I also tried with and without -Djava.compiler=NONE. (So should it be one line or multiple lines? I can't find any good documentation on java.opts.) This is my current choice:

-Xdebug
-Xrunjdwp:transport=dt_socket,address=5678,server=y,suspend=n
-Djava.compiler=NONE

2. I am using 7.4.0.287 (R2007a). The forum says MATLAB 7R14. (I don't understand this numbering.) Is my version too old?

3. I am using Eclipse 3.3.2.

4. I have tried several different ports. 1044 is not currently in use on my machine, however.

Any help would be appreciated. I've run out of ideas, and I can't find this documented anywhere else.

Thanks.

Try the following in java.opts:
-agentlib:jdwp=transport=dt_socket,address=5678,server=y,suspend=n

The -Xrunjdwp option is deprecated.

-AndyJ

"Kenneth " <nomail@email.com> wrote in message
news:gap9ke$gne$1@fred.mathworks.com...
> This seems like a good idea, but it didn't work for me. I believe I
> followed the instructions, but when I run the launcher in Eclipse, I get a
> dialog saying:
>
> Failure to connect to remote VM. Connection refused.
> Connection refused: connect
>
> This happens whether Matlab is started before the launcher or after.
>
> I made the file java.opts in C:\Program Files\Matlab\2007a\bin\win32.
>
> Possible reasons:
>
> 1. I tried putting the opts on one line or on multiple lines as in the
> forum message. I also tried with and without -Djava.compiler=NONE. (So
> should it be one line or multiple lines? I can't find any good
> documentation on java.opts.) This is my current choice:
>
> -Xdebug
> -Xrunjdwp:transport=dt_socket,address=5678,server=y,suspend=n
> -Djava.compiler=NONE
>
> 2. I am using 7.4.0.287 (R2007a). The forum says MATLAB 7R14. (I don't
> understand this numbering.) Is my version too old?
>
> 3. I am using Eclipse 3.3.2.
>
> 4. I have tried several different ports. 1044 is not currently in use on
> my machine, however.
>
> Any help would be appreciated. I've run out of ideas, and I can't find
> this documented anywhere else.
>
> Thanks.

Andy,

When I went to try what you suggested, I found the real problem. I had put java.opts in the wrong bin/arch. I do apologize.

It is apparently OK to put the opts on separate lines. This is what I am now using:

-Xdebug
-agentlib:jdwp=transport=dt_socket,address=5678,server=y,suspend=n
-Djava.compiler=NONE

It is truly awesome. Thanks to you and the others for working this out.

     -Ken

Hi.

For debugging java classes: Does anybody know if / how it is possible to connect Eclipse 3.2.1 and MATLAB 6.0.0.88 (R12) on Windows ?

Any help would be really appreciated.

BR,
Holger