Java Visualizer not working

[nileshtakale]

Hi,
I followed all the steps on my RHEL 7 64 bit OS to install Java Visualizer, but still it is not working.
safeexec is working properly.
In Java jail when I execute below command ,

./java/bin/java -cp .:cp:cp/javax.json-1.0.jar:java/lib/tools.jar traceprinter.InMemory < cp/traceprinter/test-input.txt
it gives me below output.

{"code":"public class Test { public static void main(String[] args) { int x = 3; x += x; } }","stdin":"","trace":[{"stdout":"","event":"call","line":1,"stack_to_render":[{"func_name":"main:1","encoded_locals":{},"ordered_varnames":[],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"1","frame_id":1}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}},{"stdout":"","event":"step_line","line":1,"stack_to_render":[{"func_name":"main:1","encoded_locals":{},"ordered_varnames":[],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"2","frame_id":2}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}},{"stdout":"","event":"step_line","line":1,"stack_to_render":[{"func_name":"main:1","encoded_locals":{"x":3},"ordered_varnames":["x"],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"4","frame_id":4}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}},{"stdout":"","event":"step_line","line":1,"stack_to_render":[{"func_name":"main:1","encoded_locals":{"x":6},"ordered_varnames":["x"],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"8","frame_id":8}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}},{"stdout":"","event":"return","line":1,"stack_to_render":[{"func_name":"main:1","encoded_locals":{"x":6,"return":["VOID"]},"ordered_varnames":["x","return"],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"9","frame_id":9}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}}],"userlog":"Debugger VM maxMemory: 3513M\n"}

everything is blank inside {}.

I also tried accessing Java Visualizer by http://localhost/java_visualize. but its not working.

Please help.

Thanks.

[daveagp]

Hi,

I'm copying from your email:
"""
When I access Java Visualizer from browser it is not showing default program which is ClassNameHere

When I click on Visualize Execution button, it says please wait..processing your code and does not processes anything.

I can not see frames on the left side of the screen.
"""
First, you should just get the command-line test working. Until that works, nothing else can work. When you say "everything is blank inside {}." what do you mean, compared to https://github.com/daveagp/java_jail/blob/master/cp/traceprinter/expected-output.txt ?

[nileshtakale]

Hi David,

Thanks for the quick reply. Yes, the output inside {} is blank as compared
to expected-output.txt. I mean I can not see any values inside it, the way
they are in expected-output.txt. {"REF","9"} like that.
How do I make command-line test working? I configured safeexec and
java_jail paths in jv-config.json but still its not working.

Could you please guide me so that I can go ahead?

Thanks,
Nilesh

On Sun, Sep 27, 2015 at 12:29 AM, Dave Pritchard notifications@github.com
wrote:

Hi,

I'm copying from your email:
"""
When I access Java Visualizer from browser it is not showing default
program which is ClassNameHere

When I click on Visualize Execution button, it says please
wait..processing your code and does not processes anything.

I can not see frames on the left side of the screen.
"""
First, you should just get the command-line test working. Until that
works, nothing else can work. When you say "everything is blank inside {}."
what do you mean, compared to
https://github.com/daveagp/java_jail/blob/master/cp/traceprinter/expected-output.txt
?

—
Reply to this email directly or view it on GitHub
#6 (comment).

[daveagp]

Actually this is no big deal. We added a feature where the visualizer suppresses args[] if it is an empty array and that's what's happening here.

So let's go back to your other questions:
"""
When I access Java Visualizer from browser it is not showing default program which is ClassNameHere

When I click on Visualize Execution button, it says please wait..processing your code and does not processes anything.

I can not see frames on the left side of the screen.
"""

If you do this in Chrome or some other browsers, you can use the Developer Tools to inspect Network traffic and look at the error console. (f12 in Chrome) Open this panel including Network and then re-press the visualize button (see attachment). Are there errors? What is the network reply?

[nileshtakale]

Hi David,

After turning on debugging in firefox and following above steps I am facing
JavaScript errors, please check.
Let me know what needs to be done.

Thanks,
Nilesh

On Sun, Sep 27, 2015 at 11:52 AM, Dave Pritchard notifications@github.com
wrote:

Actually this is no big deal. We added a feature where the visualizer
suppresses args[] if it is an empty array and that's what's happening here.

So let's go back to your other questions:
"""
When I access Java Visualizer from browser it is not showing default
program which is ClassNameHere

When I click on Visualize Execution button, it says please
wait..processing your code and does not processes anything.

I can not see frames on the left side of the screen.
"""

If you do this in Chrome or some other browsers, you can use the Developer
Tools to inspect Network traffic and look at the error console. (f12 in
Chrome) Open this panel including Network and then re-press the visualize
button (see attachment). Are there errors? What is the network reply?
[image: image]
https://cloud.githubusercontent.com/assets/1429912/10123986/7a28d3fe-64fd-11e5-8e0a-69886da0b16c.png

—
Reply to this email directly or view it on GitHub
#6 (comment).

[nileshtakale]

Hi,

I forgot to send network tab response.

Thanks,
Nilesh

On Sun, Sep 27, 2015 at 12:17 PM, Nilesh Takale nileshtakale@gmail.com
wrote:

Hi David,

After turning on debugging in firefox and following above steps I am
facing JavaScript errors, please check.
Let me know what needs to be done.

Thanks,
Nilesh

On Sun, Sep 27, 2015 at 11:52 AM, Dave Pritchard <notifications@github.com

wrote:

Actually this is no big deal. We added a feature where the visualizer
suppresses args[] if it is an empty array and that's what's happening here.

So let's go back to your other questions:
"""
When I access Java Visualizer from browser it is not showing default
program which is ClassNameHere

When I click on Visualize Execution button, it says please
wait..processing your code and does not processes anything.

I can not see frames on the left side of the screen.
"""

If you do this in Chrome or some other browsers, you can use the
Developer Tools to inspect Network traffic and look at the error console.
(f12 in Chrome) Open this panel including Network and then re-press the
visualize button (see attachment). Are there errors? What is the network
reply?
[image: image]
https://cloud.githubusercontent.com/assets/1429912/10123986/7a28d3fe-64fd-11e5-8e0a-69886da0b16c.png

—
Reply to this email directly or view it on GitHub
#6 (comment).

[daveagp]

I don't see any errors copied in. Start with the Javascript console errors.

[nileshtakale]

Hi,

There is syntax error, check my second attachments.

Thanks,
Nilesh

On Sun, Sep 27, 2015 at 12:54 PM, Dave Pritchard notifications@github.com
wrote:

I don't see any errors copied in. Start with the Javascript console errors.

—
Reply to this email directly or view it on GitHub
#6 (comment).

[daveagp]

There's nothing there. I am not sure you can email attachments in GitHub Issue threads. Try responding on the webpage #6 and attaching your info there directly.

[nileshtakale]

I have sent email attachments to your gmail id. Please check.

On Sun, Sep 27, 2015 at 12:58 PM, Dave Pritchard notifications@github.com
wrote:

There's nothing there. I am not sure you can email attachments in GitHub
Issue threads. Try responding on the webpage #6
#6 and attaching your info
there directly.

—
Reply to this email directly or view it on GitHub
#6 (comment).

[daveagp]

Please keep your replies on GitHub instead of email if you don't mind. So I see you have a syntax error on line 1 of config.js.php. If you click on that error, you should be able to see what the error is (like, what are the contents of that file). Can you check that?

Also, try refreshing the page and observing the network tab. Right now it only captured the "visualize" action but not the original page load.

[nileshtakale]

Hi,

When I click on Visualize execution facing below error,

[13:13:01.203] Use of getPreventDefault() is deprecated. Use
defaultPrevented instead. @
http://192.168.147.10/OnlinePythonTutor/v3/js/jquery-1.8.2.min.js:2

In network tab it goes to the URL http://192.168.147.10/example-code/ ,
thats it.

On Sun, Sep 27, 2015 at 1:03 PM, Dave Pritchard notifications@github.com
wrote:

Please keep your replies on GitHub instead of email if you don't mind. So
I see you have a syntax error on line 1 of config.js.php. If you click on
that error, you should be able to see what the error is (like, what are the
contents of that file). Can you check that?

Also, try refreshing the page and observing the network tab. Right now it
only captured the "visualize" action but not the original page load.

—
Reply to this email directly or view it on GitHub
#6 (comment).

[nileshtakale]

Hi David,

I guess there are few css and javascript errors. I can see in network tab
the request goes to http://192.168.147.10/example-code/(Default.java) and
in response tab is shows the entire code for class ClassNameHere.

Config.js.php processes jv-config.json, if it fails then it says You will
not be able to submit code.

I am facing below script errors,

[13:25:16.540] Error in parsing value for 'filter'. Declaration dropped. @

http://192.168.147.10/OnlinePythonTutor/v3/css/jquery.qtip.css:570

[13:26:51.965] SyntaxError: syntax error @
http://192.168.147.10/config.js.php:1
[13:26:52.036] Unknown property 'box-sizing'. Declaration dropped. @
http://192.168.147.10/
[13:26:52.237] syntax error @
http://192.168.147.10/example-code/(Default).java:1
[13:26:52.238] TypeError: dat.indexOf is not a function @
http://192.168.147.10/jv-frontend.js?8:101

Thanks,
Nilesh

On Sun, Sep 27, 2015 at 1:19 PM, Nilesh Takale nileshtakale@gmail.com
wrote:

Hi,

When I click on Visualize execution facing below error,

[13:13:01.203] Use of getPreventDefault() is deprecated. Use
defaultPrevented instead. @
http://192.168.147.10/OnlinePythonTutor/v3/js/jquery-1.8.2.min.js:2

In network tab it goes to the URL http://192.168.147.10/example-code/ ,
thats it.

On Sun, Sep 27, 2015 at 1:03 PM, Dave Pritchard notifications@github.com
wrote:

Please keep your replies on GitHub instead of email if you don't mind. So
I see you have a syntax error on line 1 of config.js.php. If you click on
that error, you should be able to see what the error is (like, what are the
contents of that file). Can you check that?

Also, try refreshing the page and observing the network tab. Right now it
only captured the "visualize" action but not the original page load.

—
Reply to this email directly or view it on GitHub
#6 (comment).

[nileshtakale]

Hi,

Please let me know what I need to do. Is there issue at my end?

Thanks,
Nilesh

[daveagp]

What is the actual content of config.js.php that is transmitted to you over the network? On my machine it looks like this:

[nileshtakale]

Here is the screenshot

[daveagp]

It looks like you don't have php installed, or your webserver's php module is not activated.

[nileshtakale]

Ok. I am sorry but I am not aware of installing php on webserver. In my www folder I only have html module. Could you please provide any reference so that I can move ahead?

[daveagp]

https://www.google.com/webhp?sourceid=chrome-instant&rlz=1C1LENP_enUS503US503&ion=1&espv=2&es_th=1&ie=UTF-8#es_th=1&q=rhel%20install%20php

[nileshtakale]

Hi David,

After installing php module now I am facing below error, you can see all the configuration in this screenshot. Please help.

[nileshtakale]

Hi David,

I changed java_safe_ram_maketrace.php and corrected java/bin path. I am able to get rid of java error. But Safeexec is still giving error. Please check screenshot and help.

[daveagp]

I guess your command-line visualizer is working, but it is not working with your jail. Did you try "Try with safeexec (from java_jail) ... " from the README? Did you follow all the installation steps, particularly (2) and (4)? Did you install and build safeexec?

[nileshtakale]

I did not do "Try with safeexec (from java_jail). But now I did it with

/usr/java_visualizer/safeexec-master/safeexec --chroot_dir . --exec_dir / --share_newnet --nproc 50 --mem 3000000 --nfile 30 --env_vars CLASSPATH=/cp/:/cp/javax.json-1.0.jar:/java/lib/tools.jar --exec /java/bin/java traceprinter.InMemory < /usr/java_visualizer/java_jail-master/cp/traceprinter/test-input.txt

getting below error,

error 13 (Permission denied): execve error

Command exited with non-zero status (1)
elapsed time: 0 seconds
memory usage: 0 kbytes
cpu usage: 0.000 seconds

what to do for this permission error?

[daveagp]

Did you follow steps 2 copying in all of the libraries into subfolders of the jail? I believe that can cause this error. Did you follow every other step in the instructions?

[nileshtakale]

Yes, I followed all the steps. I copied necessary library files in lib64,etc and proc. I did not do anything for /lib and /usr/lib though. My java_jail has 6 folders named java,cp,dev,etc,lib64 and proc.

[daveagp]

What about the more basic hello world example in the safeexec README?

[nileshtakale]

Yes, it does gets executed. I did check that, while installing safeexec.
Now after doing some modifications in command and location of the execution getting below error.

/usr/java_visualizer/safeexec-master/safeexec --chroot_dir . --exec_dir / --share_newnet --nproc 50 --mem 3000000 --nfile 30 --env_vars CLASSPATH=/cp/:/cp/javax.json-1.0.jar:/java/lib/tools.jar --exec /usr/java_visualizer/java_jail-master/java/bin/java traceprinter.InMemory < /usr/java_visualizer/java_jail-master/cp/traceprinter/test-input.txt

Error occurred during initialization of VM
Could not allocate metaspace: 1073741824 bytes
Command exited with non-zero status (1)
elapsed time: 1 seconds
memory usage: 67224 kbytes
cpu usage: 0.000 seconds

[daveagp]

Try increasing --mem

[nileshtakale]

this is weird..

/usr/java_visualizer/safeexec-master/safeexec --chroot_dir . --exec_dir / --share_newnet --nproc 50 --mem 30000000 --nfile 30 --env_vars CLASSPATH=/cp/:/cp/javax.json-1.0.jar:/java/lib/tools.jar --exec /usr/java_visualizer/java_jail-master/java/bin/java traceprinter.InMemory < /usr/java_visualizer/java_jail-master/cp/traceprinter/test-input.txt

Error:

Could not find or load main class traceprinter.InMemory
Command exited with non-zero status (1)
elapsed time: 0 seconds
memory usage: 0 kbytes
cpu usage: 0.052 seconds

[daveagp]

Is your pwd the jail? (I assume so since chroot_dir is . )

Double-check that the file java_jail/cp/traceprinter/InMemory.class exists and is readable by anyone

[nileshtakale]

I'm at / and yes the class exists and readable by anyone.

[nileshtakale]

It is there.

[daveagp]

Can you show me the output of "sudo find / | grep libpthread"

[nileshtakale]

Please check

[daveagp]

You need it in the exact same subfolder of jail as it appears in the root. So instead of java_jail-master/lib64, put it in java_jail-master/lib/x86_64-linux-gnu

[nileshtakale]

After copying all files from /jai/lib64 to /jail/lib, I executed below command and it gave me output.

/usr/java_visualizer/safeexec-master/safeexec --chroot_dir /usr/java_visualizer/java_jail-master --exec_dir / --share_newnet --nproc 50 --mem 30000000 --nfile 30 --env_vars CLASSPATH=./cp/:./cp/javax.json-1.0.jar:./java/lib/tools.jar --exec /java/bin/java traceprinter.InMemory < /usr/java_visualizer/java_jail-master/cp/traceprinter/test-input.txt

now what next?

[daveagp]

If that output looks more or less correct, try using the web interface again.

[nileshtakale]

Yeah, I tried but as you said "configuring the glue to the webserver" is what we need to do

[daveagp]

So what happens when you try to use the visualizer webpage now?

[nileshtakale]

Faced below error

[daveagp]

Go into java_safe_maketrace.php, uncomment the line "// echo $jv_cmd; // for debugging" and try again.

[nileshtakale]

Below is the error description,

[nileshtakale]

I do not know if I am correct or not but why it is looking at below location?

:/cp/visualizer-stdlib traceprinter.InMemory. Class file is not at that location.

[daveagp]

Not sure what you are asking me. Is "class file is not at that location" an error message? It should be there. And this worked, no?

/usr/java_visualizer/safeexec-master/safeexec --chroot_dir /usr/java_visualizer/java_jail-master --exec_dir / --share_newnet --nproc 50 --mem 30000000 --nfile 30 --env_vars CLASSPATH=./cp/:./cp/javax.json-1.0.jar:./java/lib/tools.jar --exec /java/bin/java traceprinter.InMemory < /usr/java_visualizer/java_jail-master/cp/traceprinter/test-input.txt

In that error message there is the command-line string. Try running it at the command-line manually.

[nileshtakale]

Yes, I did get output from above command.
That's what I am telling you there is no file InMemory.class at /jail/cp/visualizer-stdlib.

Command from error message

/usr/java_visualizer/safeexec-master/safeexec --chroot_dir /usr/java_visualizer/java_jail-master/ --clock 15 --cpu 10 --mem 4000000 --exec_dir / --env_vars '' --nproc 50 --nfile 50 --share_newnet --exec /usr/java_visualizer/java_jail-master/java/bin/java -Xmx512M -cp /cp/:/cp/javax.json-1.0.jar:/java/lib/tools.jar:/cp/visualizer-stdlib traceprinter.InMemory

error 2 (No such file or directory): execve error

Command exited with non-zero status (1)
elapsed time: 0 seconds
memory usage: 0 kbytes
cpu usage: 0.000 seconds

[daveagp]

I don't think you are correctly understanding what the command line is doing. It's telling java there are 4 classpath elements. The traceprinter.InMemory need not be in the 4th one.

The problem I DO see is that the generated command is wrong. Where it says "--exec /usr/java_visualizer/java_jail-master/java/bin/java" it should just say "--exec /java/bin/java" because that's the correct path once you've been chrooted. Did you make further changes to the config.json file or did you make alterations to java_safe_ram_maketrace.php?

[nileshtakale]

Ok. I had done changes in java_safe_ram_maketrace.php and changed config.json for jail and safeexec paths. After reverting changes in java_safe_ram_maketrace.php facing below error.

[nileshtakale]

Command from error message and its message,

/usr/java_visualizer/safeexec-master/safeexec --chroot_dir /usr/java_visualizer/java_jail-master/ --clock 15 --cpu 10 --mem 4000000 --exec_dir / --env_vars '' --nproc 50 --nfile 50 --share_newnet --exec /java/bin/java -Xmx512M -cp /cp/:/cp/javax.json-1.0.jar:/java/lib/tools.jar:/cp/visualizer-stdlib traceprinter.InMemory

Time Limit Exceeded
elapsed time: 15 seconds
memory usage: 2799760 kbytes
cpu usage: 0.116 seconds

[daveagp]

Try increasing the memory limit specified in the json file to 30000000.

[nileshtakale]

Same error,

Server error. Report a bug to daveagp@gmail.com (click 'Generate URL' and include it). Debug info (also copied to console):
textStatus: parsererror
errorThrown: SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data
Server reply: /usr/java_visualizer/safeexec-master/safeexec --chroot_dir /usr/java_visualizer/java_jail-master/ --clock 15 --cpu 10 --mem 30000000 --exec_dir / --env_vars '' --nproc 50 --nfile 50 --share_newnet --exec /java/bin/java -Xmx512M -cp /cp/:/cp/javax.json-1.0.jar:/java/lib/tools.jar:/cp/visualizer-stdlib traceprinter.InMemory{"code":"public class ClassNameHere {\n public static void main(String[] args) {\n \n }\n}","stdin":"","trace":[{"stdout":"","event":"call","line":4,"stack_to_render":[{"func_name":"main:4","encoded_locals":{},"ordered_varnames":[],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"1","frame_id":1}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}},{"stdout":"","event":"step_line","line":4,"stack_to_render":[{"func_name":"main:4","encoded_locals":{},"ordered_varnames":[],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"2","frame_id":2}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}},{"stdout":"","event":"return","line":4,"stack_to_render":[{"func_name":"main:4","encoded_locals":{"return":["VOID"]},"ordered_varnames":["return"],"parent_frame_id_list":[],"is_highlighted":true,"is_zombie":false,"is_parent":false,"unique_hash":"3","frame_id":3}],"globals":{},"ordered_globals":[],"func_name":"main","heap":{}}],"userlog":"Debugger VM maxMemory: 455M\n"}

[daveagp]

Re-comment out the debugging line in java_safe_maketrace.php

[nileshtakale]

Hey..its working now.

[daveagp]

Excellent! Have fun!

[nileshtakale]

Thanks a lot!

[nileshtakale]

Sorry to bother you again but after fresh installation on AWS I am getting below error,

pytutor_ajax_timeout_millis is not defined. The variable is there in config.js.php.
All commands for java jail and safeexec are executing properly.

Could you please help?

Thanks.

[daveagp]

Please start a new issue thread, not this one.

Did you remember to copy jv-config.example.json to jv-config.json as specified in the README?

[nileshtakale]

Hey...we got it resolved..we updated the PHP version and it worked.

Thanks.

[susobhang70]

Hi,
I am having a similar issue to the one mentioned in this thread. I'm on CentOS release 5.8 (Final)

When I try this command from java_jail:
/home/ssad1/safeexec/safeexec --share_newnet --nproc 50 --mem 30000000 --nfile 30 --env_vars CLASSPATH=./cp/:./cp/javax.json-1.0.jar:./java/lib/tools.jar --exec ./java/bin/java traceprinter.InMemory < cp/traceprinter/test-input.txt

Output is:
Exception in thread "event-handler" java.lang.OutOfMemoryError: unable to create new native thread
at java.lang.Thread.start0(Native Method)
at java.lang.Thread.start(Thread.java:714)
at traceprinter.JSONTracingThread.handleEvent(JSONTracingThread.java:221)
at traceprinter.JSONTracingThread.run(JSONTracingThread.java:136)
OK
elapsed time: 2 seconds
memory usage: 5092524 kbytes
cpu usage: 1.585 seconds

When I run this:
/home/ssad1/safeexec/safeexec --chroot_dir . --exec_dir / --share_newnet --nproc 50 --mem 3000000 --nfile 30 --env_vars CLASSPATH=/cp/:/cp/javax.json-1.0.jar:/java/lib/tools.jar --exec /java/bin/java traceprinter.InMemory < cp/traceprinter/test-input.txt

Output is:
Error occurred during initialization of VM
Could not allocate metaspace: 1073741824 bytes
Command exited with non-zero status (1)
elapsed time: 0 seconds
memory usage: 0 kbytes
cpu usage: 0.000 seconds

Both are run from inside the java_jail

[daveagp]

Please use a new issue. There, tell me what happens when you increase the --mem argument.