Javaで外部コマンド呼び出し

import java.io.*;
try{
    Process process = Runtime.getRuntime().exec("ls");
}catch(Exception e){
  //error
}

標準出力受け取る

  InputStream is = process.getInputStream();
  BufferedReader br = new BufferedReader(new InputStreamReader(is));
		
  String line;
  while((line = br.readLine()) != null){
	System.out.println(line);
  }
  br.close();

標準入力ぶちこむ

BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
bw.write("abc");
bw.close();