Read output git-bash with ProcessBuilder in Java

Question

I can't read the output of my git command that I run in git bash in my Java application with ProcessBuilder.

OS : Windows 8.1 --- IDE : IntelliJ

My code tries to list all the files in a github repository and count the number of java file types.

Complete git command (pipe type):

cd C:/Users/Utente/Documents/Repository-SVN-Git/Bookkeeper && git ls-files | grep .java | wc -l

The result is present in my git bash but it is not shown in my Java application and I cannot understand why this is so.

Result in git-bash :
 2140
Result in IntelliJ :
 --- Command run successfully
 --- Output=

This is my class java:

public class SelectMetrics {

public static final String path_bash = "C:/Program Files/Git/git-bash.exe";    
public static final String path_repository = "cd C:/Users/Utente/Documents/Bookkeeper";        
public static final String git_command = "git ls-files | grep .java | wc -l";        
public static final String command_pipe = path_repository + " && " + git_command;

public static void main(String[] args) {       
    runCommandPIPE(command_pipe);
}

public static void runCommandPIPE(String command) {
    try {
        ProcessBuilder processBuilder = new ProcessBuilder();
        processBuilder.command(path_bash, "-c", command);

        Process process = processBuilder.start();
        StringBuilder output = new StringBuilder();
        BufferedReader reader = new BufferedReader(
          new InputStreamReader(process.getInputStream()));

        String line;
        while ((line = reader.readLine()) != null) {
            output.append(line + "\n");
        }
        int exitVal = process.waitFor();
        if (exitVal == 0) {
            System.out.println(" --- Command run successfully");
            System.out.println(" --- Output=" + output);
        } else {
            System.out.println(" --- Command run unsuccessfully");
        }
    } catch (IOException | InterruptedException e) {
        System.out.println(" --- Interruption in RunCommand: " + e);
        // Restore interrupted state
        Thread.currentThread().interrupt();
    }
}
  
}

---- EDIT ----

I have found a way to take the git-bash output by printing it in a txt file and then reading it from my java application. Here you can find the code:

Open git bash using processBuilder and execute command in it

However I still don't understand why I can't read the output with ProcessBuilder

Answer 1

The problem should be in the use of

C:/Program Files/Git/git-bash.exe

because it opens the window that a user uses for working, but at runtime in a java application you should use

C:/Program Files/Git/bin/bash.exe

In this way ProcessBuilder can read the result of the git operations.

ProcessBuilder cannot read from the window git-bash.exe and it is correct that the result from the reading is null. If you run commands in git-bash.exe at runtime the result will be only shown in the window git-bash.exe and the java application cannot read it.

--- EDIT 2021/03/26 ---

In conclusion, for run a command with git-bash and read from it the output at runtime in your java application, you have to change my question code with:

public static final String path_bash = "C:/Program Files/Git/bin/bash.exe";

then

Result in git-bash :
2183
Result in IntelliJ :
 --- Command run successfully
 --- Output=2183