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Gazebo model path issue when starting from Java

My team is currently working on a project in Java that involves the robot simulation software Gazebo. To launch Gazebo with a specific world, we have written a shell script that we want to execute with the Runtime.getRuntime().exec(...) command in Java (or ProcessBuilder).
Here is our problem:
If we start that script from the terminal, everything works perfectly i.e. you can see a world with one of our models (pylons):
However, if we try to execute that script from within our Java application, it just shows this (models are recognized but not visualized):
We assume that Gazebo doesn't find the gazebo model path although they are defined in ~/.bashrc.
Has anyone an idea why it is not working. We know that most of you may not know Gazebo, but maybe some of you have dealt with similar issues.
Thanks in advance!

I found a solution that works for us:
Instead of the "Runtime.getRuntime().exec(...)" command, I use the ProcessBuilder.
ProcessBuilder builder = new ProcessBuilder();
builder.command(your_command);
builder.directory(new File(your_path));
Map<String, String> env = builder.environment();
env.put("GAZEBO_MODEL_PATH", variable_content);
Process process = builder.start();
Now, we can set GAZEBO_MODEL_PATH here and Gazebo loads all worlds correctly

How to run a C++ exe file from Java?

I want to open an EXE file from a Java program. I tried 2 procedures.
The program can run some programs, like NotePad++, but cannot run my C++ EXE file. I tried:
Process exec = Runtime.getRuntime().exec(file.getAbsolutePath());
ProcessBuilder processBuilder = new ProcessBuilder(file.getAbsolutePath());
but neither of the above work. No exception is thrown, and exec.isAlive = true.

Your mistake is that you took the absolute path in the first procedure.
Try using a relative path, I just tested and it worked just fine.
This also works for me (using 2 backslashs').
Runtime.getRuntime().exec("C:\\Program Files\\DDNet\\DDNet.exe");
Kind regards

Java calls wrong python version

I'm trying to run a Python script from a Java program using Process and ProcessBuilder, however Java keeps using the wrong version of Python. (The script needs 3.6.3 to run and Java runs Python 2.7)
However when I run the script from the terminal (outside of Java), it runs the correct Python (3.6.3). How does one change what version of Python gets run when called by Java?

The short version is it changes with your PATH environment variable.
Under Windows, Technet has the answer. Scroll down to the 'Command Search Sequence' section. This answer explains it nicely.
For UNIX-like OS's, this answer is nicely detailed.
There are two very useful commands for determining which executable is going to be called: which for UNIX-likes and where for newer Windows.
The most likely reason for the difference between Java and the terminal is a difference in your PATH. Perhaps your Java version is being run with a modified PATH? A launch script of some kind may be changing it.

Add /usr/bin/python3.4 to the start of your command to force the version of python you want. If you're not sure where python is installed, have a go at using whereis python and seeing what you get back.
private int executeScript(final List<String> command) {
try {
final ProcessBuilder processBuilder = new ProcessBuilder("/usr/bin/python3.4").command(command);
processBuilder.redirectErrorStream(true);
System.out.println("executing: " + processBuilder.command().toString());
final Process process = processBuilder.start();
final InputStream inputStream = process.getInputStream();
final InputStream errorStream = process.getErrorStream();
readStream(inputStream);
readStream(errorStream);
return process.waitFor();
} catch (Exception e) {
System.out.println(e.getMessage());
}
return -1;
}
Then just pass in the List containing your python commands.

Run jar file from java application [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Run Java program into another Program
i try to run jar file from java application which was created in eclipse.
when i run jar file using below source code then fire Unable to access jarfile error
Process process = run.exec("java -jar TestJava.jar");
InputStream inError = process.getErrorStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inError));
System.out.println("Error=" + bufferedReader.readLine());

Sounds like TestJava.jar is in a different directory. If you're running this code within Eclipse, then the present working directory is going to be the same as your Eclipse project's folder (unless you've configured it differently, this is Eclipse's default run location). Either specify a path to TestJava.jar via an absolute path or a path relative to the present working directory.
One other thing you'll need to be mindful of - you need to consume both the error stream and the output stream of the Process you're creating. The default output/error stream buffer sizes of Process instances are not very big and, if full, will cause that Process to block indefinitely for more buffer space. I recommend consuming each stream in a separate Thread.

Set the working directory where this process should run. Set the working directory using the below statement.
Runtime.getRuntime().exec(command, null, new File("path_to_directory"));

First try the java -jar command on cmd window and see if you can run TestJava.jar. Then try running the same command from your code.
Runtime runtime = Runtime.getRuntime();
Process proc = runtime.exec("java -jar TestJava.jar");
System.exit(0);

You need to supply the full path to the Java command.
For example, under windows you'd need something like
C:/Program Files/java/jre/bin/java.exe
ProcessBuilder & Runtime.exec don't take the system path into account when trying to execute your command

How to run a script from Java

I have a script, which is test.sh on Ubuntu. I want to run it from Java. I know I have to use Runtime.getRuntime().exec();
Don't I have to fill the exec parenthesis with the location of test.sh? I am typing /home/main/ss/test.sh
I do not get any error messages but when I searched the folder, I saw that script did not work. How can I fix it?

You should really look at Process Builder. It is really built for this kind of thing.
ProcessBuilder pb = new ProcessBuilder("myshellScript.sh", "myArg1", "myArg2");
Map<String, String> env = pb.environment();
env.put("VAR1", "myValue");
env.remove("OTHERVAR");
env.put("VAR2", env.get("VAR1") + "suffix");
pb.directory(new File("myDir"));
Process p = pb.start();

Did you try to call your script directly, or did you specify a shell to use? You may need to specify the shell on your exec call if it's not specified (and processed) from the first line of the script.

From looking at your description, how you conclude the script didn't work:
I do not get any error messages but when I searched the folder, I saw
that script did not work. How can I fix it?
I conclude, the script creates a new file, and there is none, after starting from Java.
Maybe you assume, that the output of the script will, if sent to the current directory, end in the directory of the script, not in the directory where you started your Java application.
This might be the Desktop, if you start your class from the UI with an Icon as starter, it might be your home or project dir, if you compile the class from hand, or a directory, set up by your IDE, if you develop with eclipse or the like.
If your script writes to an absolute path like /tmp/script.out, you could verify fast, whether this might be your issue.