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Can't call Gradle with arguments from a java app using Process Builder, build fails

I'm trying to call a Gradle app from a separate java app, on Linux. I'm using ProcessBuilder, which calls the Gradle app no problem when not passing an argument, and the Gradle app builds. But when I include an argument, it doesn't appear to run Gradle at all, but doesn't give an error, and still prints Processbuilder run to the Terminal.
This is in the main method:
String cmd = "./gradlew";
try {
String lines = null;
//This works but doesn't send an argument:
//ProcessBuilder pb = new ProcessBuilder(cmd, "run");
//won't run with an argument!
ProcessBuilder pb = new ProcessBuilder(cmd, "run", "argy");
Process pr = pb.start();
System.out.println("Processbuilder run");
BufferedReader reader = new BufferedReader(new InputStreamReader(pr.getInputStream()));
while ((lines = reader.readLine())!=null) {
System.out.println("Line: " + lines);
}
}
catch (IOException e)
{
System.out.print("error");
e.printStackTrace();
}
}
Terminal output when run ProcessBuilder without argy :
Processbuilder run
Line: > Task :app:compileJava
Line: > Task :app:processResources
Line: > Task :app:classes
Line:
Line: > Task :app:run
Line:
Line: BUILD SUCCESSFUL in 1s
Line: 3 actionable tasks: 3 executed
`
Terminal output when run ProcessBuilder with argy :
Processbuilder run
I need to pass java objects through so I can't use Runtime.getRuntime().exec() as it only passes through a string as an argument.
How can I get ProcessBuilder to supply the argument to Gradle and have it run? Or is there some other way of calling a Gradle app from a totally separate java package?

After placing pb.redirectErrorStream(true); before pb.start(), it became clear that I was passing "argy" as a command not an argument.
To run gradle, you need the command ./gradlew run --args="string_args" so I edited it to:
String argy= "argybargy\"";
String myArg = String.format("--args=\" %s", argy);
try {
String lines = null;
ProcessBuilder pb = new ProcessBuilder("./gradlew", "run", myArg);
pb.redirectErrorStream(true);
Process pr = pb.start();
System.out.println("Processbuilder run");
BufferedReader reader = new BufferedReader(new InputStreamReader(pr.getInputStream()));
while ((lines = reader.readLine())!=null) {
System.out.println("Line: " + lines);
}
}
catch (IOException e)
{
System.out.print("error");
e.printStackTrace();
}
Which now runs, passes the argument correctly, and redirects any errors to the terminal. Many thanks for all the help.

Using ProcessBuilder to compile multiple java files throws File not found error

I have simple java program for compiling java classes.
I created a JAR of this program and when I run it on Ubuntu I pass to the jar the path of folder with java files.
public class Main {
public static void main(String[] args) throws IOException, InterruptedException {
compile(args[0]);
}
//pathToFiles - is a value from command line arguments
private static void compile(String pathToFiles) throws IOException, InterruptedException {
List<String> cmdList = new ArrayList<>();
cmdList.add("javac");
cmdList.add(pathToFiles);
System.out.println("cmd: "+cmdList);
ProcessBuilder pb = new ProcessBuilder(cmdList);
Process process = pb.start();
int exitValue = process.waitFor();
if (exitValue != 0) {
generateCompileException(process);
}
}
//method just generates error message if there was an error
private static void generateCompileException(Process process){
StringBuilder response = new StringBuilder();
try (final BufferedReader b = new BufferedReader(new InputStreamReader(process.getErrorStream()))) {
String line;
if ((line = b.readLine()) != null)
response.append(line);
} catch (final IOException e) {
e.printStackTrace();
}
throw new RuntimeException(response.toString());
}
}
When I pass path containing single java file it works:
java -jar co-1.jar /home/admin/test2/Calculator.java
But I want to compile multiple files. When I pass path containing multiple files I get error: file not found.
java -jar co-1.jar '/home/admin/test2/*.java'
PS: If I run a javac command manually with multiple files, it will work:
###################################
UPDATE:
I've added bash command to ProcessBuilder:
private static void compile(String pathToFiles) throws IOException, InterruptedException {
List<String> cmdList = new ArrayList<>();
cmdList.add("bash");
cmdList.add("-c");
cmdList.add("javac");
cmdList.add(pathToFiles);
System.out.println("Processor builder command: "+cmdList);
ProcessBuilder pb = new ProcessBuilder(cmdList);
Process process = pb.start();
int exitValue = process.waitFor();
if (exitValue != 0) {
System.out.println("Finished with error. Exit value: "+exitValue);
generateCompileException(process);
}
}
But process withished with error code 2 with empty response from ProcessBuilder.
PS: RuntimeException was thrown by this line: throw new RuntimeException(response.toString());

ProcessBuilder will not evaluate wildcards, as that is a feature of your terminal (such as bash). If you want wildcard to be expanded you need to run bash inside ProcessBuilder command, such as:
String commandContainingWildcard = "javac /blah/*.java";
ProcessBuilder pb = new ProcessBuilder("bash", "-c", commandContainingWildcard);
... // start() etc
For the above to work you need to have "bash" or whatever shell you use in your path, otherwise you will need to use full path to bash (such as "/bin/bash").
The third argument for command to compile must exactly match what works inside your terminal and must be the entire value not "javac" followed by wildcard. Remove single quotes around *.java (so that ProcessBuilder is provided with three command line parameters, not four or more).
However I suggest that ProcessBuilder with bash isn't the best way to do this work. You could try Java compiler tool interface, and get rid of wildcard by easy use of Files.find(dir, 1, (p,a) -> p.getFileName().toString().endsWith(".java")) to scan for all java files and join the paths explicitly for compilation.
UPDATE
Having now resolved your problem you may now find that the javac process fails / freezes due the incorrect way you read the stderr stream - this needs to happen at same time as stdout and before process.waitFor(). An easy fix is to consume stdout+stderr together:
ProcessBuilder pb = new ProcessBuilder(cmdList);
pb.redirectErrorStream(true);
Process process = pb.start();
ByteArrayOutputStream response = new ByteArrayOutputStream();
process.getInputStream().transferTo(response);
int exitValue = process.waitFor();
if (exitValue != 0) {
System.out.println("Finished with error. Exit value: "+exitValue);
throw new RuntimeException(new String(response.toByteArray()));
}

Remove quotes and use the command as below.
java -cp co-1.jar:/home/admin/test2/* Main.class <args>
See also
https://docs.oracle.com/javase/7/docs/technotes/tools/windows/classpath.html
PS: Unix uses :(colon) as delimiter and windows uses ;(semi-colon) delimiter to separate multiple paths.

java command execution escapes '|'

I have a function to execute a system command:
public String cmd(String s) {
String out = "";
try {
Runtime run = Runtime.getRuntime();
Process pr = run.exec(s.split(" "));
pr.waitFor();
BufferedReader buf = new BufferedReader(new InputStreamReader(pr.getInputStream()));
String line = "";
while ((line=buf.readLine())!=null) {
out+=line+"\n";
}
} catch(Exception e) {
e.printStackTrace();
}
return out;
}
The command passes through:
cmd("nmap -sL -n 192.168.1.0/24 | awk '/Nmap scan report/{print $NF}'");
Expected Output:
192.168.1.0
192.168.1.1
...
Actual Output:
Starting Nmap 7.80 ( https://nmap.org ) at 2021-04-12 20:27 EET
Nmap scan report for 192.168.1.0 ...

Similar questions answers this well:
Using Java ProcessBuilder to Execute a Piped Command
Java program not getting output from terminal
To execute a pipeline, you have to invoke a shell, and then run your commands inside that shell.
Process p = new ProcessBuilder().command("bash", "-c", command).start();
bash invokes a shell to execute your command and -c means commands are read from string. So, you don't have to send the command as an array in ProcessBuilder.
Adapted to you case
String cmd(String command) {
ProcessBuilder builder = new ProcessBuilder();
builder.redirectErrorStream(true); // add stdErr to output
Process process = builder.command("bash", "-c", command).start();
StringBuilder processOutput = new StringBuilder(); // add lines easier
// try-with to auto-close resources
try (BufferedReader processOutputReader = new BufferedReader(new InputStreamReader(process.getInputStream()));) {
String readLine;
while ((readLine = processOutputReader.readLine()) != null) {
processOutput.append(readLine + System.lineSeparator()); // use system's line-break
}
process.waitFor();
}
return processOutput.toString().trim();
}
Then call as expected:
cmd("nmap -sL -n 192.168.1.0/24 | awk '/Nmap scan report/{print $NF}'");
Note: I enhanced it a bit to
use try-with-resources to deal cleanly with resources
add output from StdErr
use a StringBuilder to concatenate output lines
use System.lineSeparator for platform-independency (Win/Mac/Linux/Unix)
Inspired by:
read the output from java exec

The pipe is interpreted by the shell. It executes one command then passes the output of one command into the next one. You could emulate this in Java starting both commands and then pumping the OutputStream of the first program to the InputStream of the second.
Alternatively if you don't want to do this you can still call something like "sh -c 'command1 | command2"

getting error from java

How can I call a shell script through java code?
I have writtent the below code.
I am getting the process exit code as 127.
But it seems my shell script in unix machine is never called.
String scriptName = "/xyz/downloads/Report/Mail.sh";
String[] commands = {scriptName,emailid,subject,body};
Runtime rt = Runtime.getRuntime();
Process process = null;
try{
process = rt.exec(commands);
process.waitFor();
int x = process.exitValue();
System.out.println("exitCode "+x);
}catch(Exception e){
e.printStackTrace();
}

From this post here 127 Return code from $?
You get the error code if a command is not found within the PATH or the script has no +x mode.
You can have the code below to print out the exact output
BufferedReader stdInput = new BufferedReader(new InputStreamReader(process.getInputStream()));
String s= null;
while ((s = stdInput.readLine()) != null) {
System.out.println(s);
}
BufferedReader stdOut = new BufferedReader(new InputStreamReader(process. getErrorStream()));
String s= null;
while ((s = stdOut.readLine()) != null) {
System.out.println(s);
}

If you are getting an exit code, then your script is executed. There is a command that you are running inside of "Mail.sh", which is not succeccfully executed and returning a status code of 127.
There could be some paths that are explicitly set in your shell, but is not available to the script, when executed outside of the shell.
Try this...
Check if you are able to run /xyz/downloads/Report/Mail.sh in a shell terminal. Fix the errors if you have any.
If there are no errors when you run this in a terminal, then try running the command using a shell in your java program.
String[] commands = {"/bin/sh", "-c", scriptName,emailid,subject,body};
(Check #John Muiruri's answer to get the complete output of your command. You can see where exactly your script is failing, if you add those lines of code)

how to launch a shell script in a new gnome terminal, from a java program

I'm trying to run a shell script (say myscript.sh) from a java program.
when i run the script from terminal, like this :
./myscript.sh
it works fine.
But when i call it from the java program, with the following code :
try
{
ProcessBuilder pb = new ProcessBuilder("/bin/bash","./myScript.sh",someParam);
pb.environment().put("PATH", "OtherPath");
Process p = pb.start();
InputStreamReader isr = new InputStreamReader(p.getInputStream());
BufferedReader br = new BufferedReader(isr);
String line ;
while((line = br.readLine()) != null)
System.out.println(line);
int exitVal = p.waitFor();
}catch(Exception e)
{ e.printStackTrace(); }
}
It doesnt goes the same way.
Several shell commands (like sed, awk and similar commands) get skipped and donot give any output at all.
Question : Is there some way to launch this script in a new terminal using java.
PS : i've found that "gnome-terminal" command launches a new terminal in shell,
But, i'm unable to figure out, how to use the same in a java code.
i'm quite new to using shell scripting. Please help
Thanks in advance

In java:
import java.lang.Runtime;
class CLI {
public static void main(String args[]) {
String command[] = {"/bin/sh", "-c",
"gnome-terminal --execute ./myscript.sh"};
Runtime rt = Runtime.getRuntime();
try {
rt.exec(command);
} catch(Exception ex) {
// handle ex
}
}
}
And the contents of the script are:
#!/bin/bash
echo 'hello!'
bash
Notes:
You'll do this in a background thread or a worker
The last command, in the shell script, is bash; otherwise execution completes and the terminal is closed.
The shell script is located in the same path as the calling Java class.

Don't overrwrite your entire PATH...
pb.environment().put("PATH", "OtherPath"); // This drops the existing PATH... ouch.
Try this instead
pb.environment().put("PATH", "OtherPath:" + pb.environment().get("PATH"));
Or, use the full directories to your commands in your script file.

You must set your shell script file as executable first and then add the below code,
shellScriptFile.setExecutable(true);
//Running sh file
Process exec = Runtime.getRuntime().exec(PATH_OF_PARENT_FOLDER_OF_SHELL_SCRIPT_FILE+File.separator+shellScriptFile.getName());
byte []buf = new byte[300];
InputStream errorStream = exec.getErrorStream();
errorStream.read(buf);
logger.debug(new String(buf));
int waitFor = exec.waitFor();
if(waitFor==0) {
System.out.println("Shell script executed properly");
}

This worked for me on Ubuntu and Java 8
Process pr =new ProcessBuilder("gnome-terminal", "-e",
"./progrm").directory(new File("/directory/for/the/program/to/be/executed/from")).start();
The previous code creates a new terminal in a specificied directory and executes a command

script.sh Must have executable permissions
public class ShellFileInNewTerminalFromJava {
public static void main(String[] arg) {
try{
Process pr =new ProcessBuilder("gnome-terminal", "-e", "pathToScript/script.sh").start();
}catch(Exception e){
e.printStackTrace();
}
}
}