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How to use ProcessBuilder with bash -c, if the command has double quotes

I have to join two huge files based on multiple columns. Pipe(|) symbol is the delimiter in both files.
Right now, I am generating unix join command, writing it to a shell script and then executing the shell script using ProcessBuilder to get the desired output.
The command looks something like this,
join -a 1 -a 2 -t \| -1 1 -2 1 -o 1.3,1.4,1.5,1.6,1.7,2.3,2.4,2.5,2.6,2.7 <(<"/home/input file 1" awk -F'|' 'NR>1{print $3"~&~"$4"|"$0}' | sort -k1 -t\| ) <(<"/home/input file 2" awk -F'|' 'NR>1{print $3~&~$4"|"$0}' | sort -k1 -t\| ) > "/home/output file"
This is working as expected.
I am trying to omit the step of writing the command to a shell script by using bash -c. But I am running into issues mainly because of the double quotes(") and dollar($) in the awk command. I tried to escape them using backward slash, but was of no use.
the java code I am using currently is
long pid = -1;
try {
StringBuilder completeCommand = new StringBuilder();
for(String s: commands){
completeCommand.append(s);
completeCommand.append(" ");
}
completeCommand.append(" > \"");
completeCommand.append(outputDir + File.separator + outputFileName);
completeCommand.append("\"");
File fileOutputDir = new File(outputDir);
fileOutputDir.mkdirs();
Files.writeString(Path.of(outputDir + File.separator + scriptName),
completeCommand.toString(),
new OpenOption[]{StandardOpenOption.TRUNCATE_EXISTING, StandardOpenOption.WRITE,
StandardOpenOption.CREATE});
ProcessBuilder processBuilder = new ProcessBuilder("bash", "\"" + outputDir + File.separator + scriptName + "\"");
Process p = processBuilder.start();
pid = p.pid();
p.waitFor();
return pid;
} catch (IOException | InterruptedException e) {
log.error("Error in running join command" , e);
return pid;
}
When I tried to use bash -c, I just changed the ProcessBuilder statement like below,
ProcessBuilder processBuilder = new ProcessBuilder("bash", "-c", completeCommand.toString());
This doesn't throw any error, but it generates an empty file.
Is there any way I can solve this issue ?
Any help or suggestions would be great.
Thanks

Java Run Command pipe on linux

I am trying to get output of piped command in linux environment but so far no luck.
ProcessBuilder pb = new ProcessBuilder("/bin/sh", "-c", "top", "-b", "-n", "2", "-d", "0.2", "-p", pid + "", "|", "tail", "-1", "|", "awk", "'{print $6}'");
pb.redirectErrorStream(true);
Process p = pb.start();
p.getOutputStream().close();
try (InputStream is = p.getInputStream()) {
try (BufferedReader br = new BufferedReader(new InputStreamReader(is))) {
String line = br.readLine();
System.out.println(line);
}
}
This outputs: top: failed tty get
When I try that without specifying the script executor (/bin/bash -c): top: unknown option '|'

The shell command should be a single argument passed after -c. The invoked shell will take care of the piping and tokenization:
ProcessBuilder pb = new ProcessBuilder("/bin/sh", "-c",
"top -b -n 2 -d 0.2 -p " + pid + " | tail -1 | awk '{print $6}'");
For robustness bonus points, pass the variables as separate arguments instead of injecting them into the string (like how you'd use prepared statements in SQL):
ProcessBuilder pb = new ProcessBuilder("/bin/sh", "-c",
"top -b -n 2 -d 0.2 -p \"$1\" | tail -1 | awk '{print $6}'", "_", String.valueOf(pid));
It makes no difference when pid is an integer, but if it's an arbitrary string, this improves security and robustness.

Check if a linux command outputs an empty string

I want to check if a port is being used or not. I've used the command: netstat -an | grep <port_no> | grep -i listen. When I compare its output by running, if(message_port_check.equals(null)), it always returns null. How do I know if the port is open or not ?
This is what I've tried,
String port_no = textField_3.getText().toString();
String[] command_port = {
"/bin/sh",
"-c",
"netstat -an | grep " + port_no + " | grep -i listen"
};
try {
ProcessBuilder builder = new ProcessBuilder(command_port);
builder.redirectErrorStream(true);
Process p = builder.start();
BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
StringBuffer buffer = new StringBuffer();
String line = "";
while (true)
{
buffer.append(line).append("\n");
line = r.readLine();
if (line == null) { break; }
}
message_port= buffer.toString();
p.waitFor();
r.close();
}
catch (IOException e1)
{
e1.printStackTrace();
}
catch (InterruptedException e1)
{
e1.printStackTrace();
}
if(message_port_check.equals(null))
rdbtn_port_free.setSelected(true);
else
rdbtn_port_notfree.setSelected(true);

I'd use -z test:
$ output=$(netstat -an | grep your_port | grep -i listen)
$ if [ -z "$output" ] ; then echo empty ; fi
empty

You could use nc instead as shown in this reply. Then you just need to check the return value.
Of course in Java, the solution in the platform-independent spirit would be to try to connect/bind to the port using the standard library instead of relying on external Linux binaries. Some variants are shown here.

Unable to get output from shell script command in java

I'm running a shell script command in java program using ProcessBuilder, here is my code :
String lastLine = "";
ProcessBuilder processBuilder = new ProcessBuilder("/bin/bash", "-c", "echo $(ps -eo pid,args | grep -v grep | grep -v \"$$"\ | grep feature_service.sh | awk '{print $1}')");
BufferedReader reader =
new BufferedReader(new InputStreamReader(process.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
lastLine = line;
}
Output from this : empty string ("")
But if i run the same command on terminal it is working fine (pid of process).
Please help me.

Following simplified Shell command is working.
ProcessBuilder processBuilder = new ProcessBuilder("/bin/bash",
"-c",
"ps -eo pid,args|grep [f]eature_service.sh|awk '{print $1}'|tr '\\n' ' '");
ps -eo pid,args - list the process ID and the arguments
grep [f]eature_service.sh - grep for the string feature_service.sh in the arguments, the [f] avoid the multiple usage of grep in the chain
awk '{print $1}' - print the first column of the output, using default whitespace characters as delimiter
tr '\n' ' ' - replace all newline cracaters in the output by a space character

pipe Unix commands together in Java

I have a requirement to run the below command from Java
echo <inputMessage> | iconv -f utf8 -t Cp930
When i use the below code to run the command i see only the echo part is executed but the piping is not happening
public static String callInconverter2(String input,String codePage) throws IOException {
try{
// String command = "echo asdasdasd | iconv -f UTF-8 -t Cp930";
Process p = Runtime.getRuntime().exec("echo "+input+"| iconv -f UTF-8 -t "+codePage);
String s = null;
BufferedReader stdInput = new BufferedReader(new
InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new
InputStreamReader(p.getErrorStream()));
StringBuilder sb = new StringBuilder();
// read the output from the command
System.out.println("Here is the standard output of the command:\n");
while ((s = stdInput.readLine()) != null) {
sb.append(s);
}
// read any errors from the attempted command
System.out.println("Here is the standard error of the command (if any):\n");
while ((s = stdError.readLine()) != null) {
sb.append(s);
}
return sb.toString();
}
catch (IOException e) {
System.out.println("exception happened - here's what I know: ");
e.printStackTrace();
return e.getMessage();
}
}}
I am new to Runtime. is there anything am missing.
Tried the method suggested by thomas
String command = "echo asdasdasd | iconv -f UTF-8 -t Cp930";
Process p = Runtime.getRuntime().exec("bash -c \""+command+"\"");
was getting an error asdasdasd: -c: line 0: unexpected EOF while looking for matching `"'asdasdasd: -c: line 1: syntax error: unexpected end of file
is there anything am missing out

Run a shell, with that command -- bash, tcsh, whichever one you normally use.
bash -c "echo | iconv -f utf8 -t Cp930" // or
bash -lc "echo | iconv -f utf8 -t Cp930"
Piping is a shell functionality.
Thus:
Runtime rt = Runtime.getRuntime();
String cmd = "echo | iconv -f utf8 -t Cp930";
rt.exec("bash -c \""+cmd+"\"");
See the bash manual for invocation options. http://www.gnu.org/software/bash/manual/html_node/Invoking-Bash.html#Invoking-Bash