Alternate to print greater than (>) symbol in Ubuntu

May be this question is too easy but it took a lot my time but I could not figure out. I am trying to execute echo command in which I am trying to append some data in a text file. Everything works when run in terminal but when I try to run it through Runtime.getRuntime().exec("echo my text >> file.txt"), then >> does not work.

Is there any way to give code or something so that this command should work? I tried > but it did not work for me.

The problem is: In which shell should the echo command be executed? Runtime.exec can get a cmdArray. http://docs.oracle.com/javase/7/docs/api/java/lang/Runtime.html#exec%28java.lang.String[],%20java.lang.String[]%29

import java.io.*;

class RuntimeExecLinux {
  public static void main(String[] args){
      try {
        // Execute a command with arguments
        String[] cmd = new String[]{"/bin/bash", "-c", "echo 'my text from java' >> file.txt"};
        Process child = Runtime.getRuntime().exec(cmd);

        cmd = new String[]{"/bin/bash", "-c", "cat file.txt"};
        child = Runtime.getRuntime().exec(cmd);

        // Get the input stream and read from it
        InputStream in = child.getInputStream();
        int c;
        while ((c = in.read()) != -1) {
            System.out.print((char)c);
        }
        in.close();

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

Greetings

Axel