I am getting the following error when running the main method from InMemory and inputting the text from test-input.txt.

I notice if I remove the highlighted line, I get output similar to the expected output, but it differs in the that there is an exception message as shown below.

I have tried changing the classpath manually in the program to a few things, but not much changes. I am not very experienced in programming, so this may be a small error I don't see.

Hi Dave, amazing work on the visualizer!

My problem is that after installation on Ubuntu server (Vbox) and connecting through browser on host the Visualizer freezes after clicking "Visualize Execution".

Can you help?

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.

Hi,
I am using java_jail to install on my linux 64bit machine having cent OS 5.0 version
I used the same procedure which is given in readme file. just not added iptable
entry and It fails in both the cases when
1>run the java class InMemory by given java file as input parameter it gives null pointer exception.I think in run method of the "JSONTracingThread" JVM doesnt starts
2>in compile file given in java_jail/cp/traceprinter it is written that for testing use
following command "java traceprinter.JSONTrace Filename" but on running this it shows exception of class not found JSONTrace.
3>I have used safeexec and followed the same procedure what was given but after run it gives exception of file not found execve error

I did the same thing except one thing of IPTABLES setting.
so I want to ask
is it showing null pointer exception because of blocking of port which JVM is using while running
OR other reason?

thanks

Hello,
at first I have the same issue # 6 issue, I tried to solve with the tips you gave it. However I come across this error.

Can you help me?

While debugging the java program , VMDisconnectedException happening frequently Even before the program getting started to debugged.

Hi,
I am having an issue with safeexec and java_jail. I'm on CentOS release 5.8 (Final)

When I try this command from java_jail (i.e. without chroot):
/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

When I subsequently increase --mem, here is what i get:
1. 4000000
/home/ssad1/safeexec/safeexec --chroot_dir . --exec_dir / --share_newnet --nproc 50 --mem 4000000 --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

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: 0.004 seconds

2. 5000000

/home/ssad1/safeexec/safeexec --chroot_dir . --exec_dir / --share_newnet --nproc 50 --mem 5000000 --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
#

Command exited with non-zero status (1)
elapsed time: 1 seconds
memory usage: 4824000 kbytes
cpu usage: 1.353 seconds

3. 6000000
/home/ssad1/safeexec/safeexec --chroot_dir . --exec_dir / --share_newnet --nproc 50 --mem 6000000 --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
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: 5092532 kbytes
cpu usage: 1.482 seconds

Going above 6000000 produces the same result over and over again

when i test java_jail and safeexec separately，they both work well，but when i test java_jail with safeexec, exception happens:

I search online and it said that maybe the memory issue, what should i do ? Can i put a smaller parameter to --mem?

(1) Run this command (from java_jail):
./java/bin/java -cp .:cp:cp/javax.json-1.0.jar:java/lib/tools.jar traceprinter.InMemory < cp/traceprinter/test-input.txt

(2) Try with safeexec (from java_jail):
/path/to/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

(1) working fine but when i am running safexec i am getting below error. unable to debug it.

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