java_get_process_output.java

StringBuilder sb = new StringBuilder();

try {
    String line;
    Process p = Runtime.getRuntime().exec("npm outdated --json");
    BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
    while ((line = input.readLine()) != null) {
        sb.append(line);
    }
    input.close();
}
catch (Exception err) {
    err.printStackTrace();
}

System.out.println(sb.toString());