错误：启动进程构建器命令时无法访问 jarfile

Question

I build one program in Java with a main into a jarfile and I want to executable an other. The second program is also a jarfile.

To execute the second program, I use a process builder to execute the second jarfile with these arguments. But i didn't worked and I have this message:

Error: Unable to access jarfile path/second_program.jar

In first, I think its the path was wrong. But, I have execute the second jarfile in a terminal on windows and on linux whitout any problem.

//IN THE FIRST PROGRAM
                Process process = null;
                List<String> commands = new ArrayList<String>();

                if (server.equals("TEST_linux")) {
                    commands.add("/bin/java");
                    commands.add("-jar");
                    commands.add("/mnt/c/Users/second_program.jar");
                    commands.add("param1");
                    commands.add("param2");
                } else {
                    commands.add("java");
                    commands.add("-jar");
                    commands.add("C:/Users/second_program.jar");
                    commands.add("param1");
                    commands.add("param2");                    
                }
                System.out.println(commands);
                //Execution de la commande externe
                ProcessBuilder pb = new ProcessBuilder(commands);
                System.out.println(pb.directory());
                pb.directory(new File(localFolder));
                System.out.println(pb.directory());

                pb.redirectErrorStream(true);
                process = pb.start();
                StringBuilder out = new StringBuilder();
                BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream()));
                String line = null, previous = null;

                file_generated_by_second_program = output_folder + "/" + panel + "/file_generated_by_second_program.txt";

                myFile = new File(file_generated_by_second_program);
                writer = new BufferedWriter(new FileWriter(myFile, true));
                System.out.println(br.readLine());

All of the rest of the first program is executing perfectly. I use the first program which generated arguments to execute the second program which generate a file. This file is used after in the first program... I can't launch the second program separatly...

Any ideas?

UPDATE:

Here, these errors:

//Windows before suggestions :
Error: Unable to access jarfile C:/Users/second_program.jar

//Windows after suggestions : 
Error: Unable to access jarfile C:\Users\second_program.jar

//Linux :
Error: Unable to access jarfile "/mnt/c/Users/second_program.jar"

System.out.println(br.readLine()); //==> this command doesn't execute too!

After the last row of my code, I create differents variables and these variables existing and there are no null. So for me, the problem is limited to the extract of my code...

SOLVED: I had an error in path...sorry

Answer 1

This is related to different path separator characters:

• Windows is using "\"
• Linux is using "/"

Usually, following problem can be solved by using File.separator property, which will return the right character basing on OS that you are running. However, i can see that you are most likely using WSL, so it might not work in this case and you would have to hard-code this.

Summing up, you need to fix path to jar for Windows and differentiate output paths for both OS.