How to do a backup from a Postgresql-DB via JDBC?

Question

In our application, we've implemented an automatic DB migration triggered from within our code. Now we want to backup the existing DB before doing any migration.

Can anyone explain how to do a full backup of a Postgresql-DB via JDBC from within Java code?

Update: it doesn't work via JDBC.

Here some working code to the response of Frank Heikens:

    final List<String> baseCmds = new ArrayList<String>();
    baseCmds.add("/usr/bin/pg_dump");
    baseCmds.add("-h");
    baseCmds.add("hostname");
    baseCmds.add("-p");
    baseCmds.add("5432");
    baseCmds.add("-U");
    baseCmds.add("username");
    baseCmds.add("-b");
    baseCmds.add("-v");
    baseCmds.add("-f");
    baseCmds.add("/path/to/backup.sql");
    baseCmds.add("dbName");
    final ProcessBuilder pb = new ProcessBuilder(baseCmds);

    // Set the password
    final Map<String, String> env = pb.environment();
    env.put("PGPASSWORD", "password");

    try {
        final Process process = pb.start();

        final BufferedReader r = new BufferedReader(
                  new InputStreamReader(process.getErrorStream()));
        String line = r.readLine();
        while (line != null) {
            System.err.println(line);
            line = r.readLine();
        }
        r.close();

        final int dcertExitCode = process.waitFor();

     } catch (IOException e) {
        e.printStackTrace();
     } catch (InterruptedException ie) {
        ie.printStackTrace();
     }

Answer 1

Why don't you use pg_dump?