java execShell

public static List<String> execShell(String workspace, String... shellStrings) {
        List<String> resultList = new ArrayList<>();
        StringBuilder msg = new StringBuilder();
        File dir = null;
        if (workspace != null) {
            msg.append(String.format("execShell workspace=%s\n", workspace));
            dir = new File(workspace);
        }
        for (String shellString : shellStrings) {
            msg.append(String.format("pre-execShell %s", shellString));
            StringBuilder result = new StringBuilder();
            try {
                Process process;
                if (IS_OS_WINDOWS) {
                    process = Runtime.getRuntime().exec(shellString, null, dir);
                } else {
                    process = Runtime.getRuntime().exec(new String[]{"/bin/sh", "-c", shellString}, null, dir);
                }
                try (LineNumberReader input = new LineNumberReader(
                        new InputStreamReader(process.getInputStream(), StandardCharsets.UTF_8))) {
                    String line;
                    while ((line = input.readLine()) != null) {
                        result.append(line).append("\n");
                    }
                }
            } catch (Exception e) {
                log.error("execShell", e);
                result.append("ERROR: " + e.getMessage()).append("\n");
            }
            msg.append(String.format("\npost-execShell %s\n\n", result));
            if (result.getLength() == 0) {
                result.append("NULL");
            }
            resultList.add(result.toString());
        }
        log.info(msg.toString());
        return resultList;
    }