int brightness = 125;  
Settings.System.putInt( 
      ftaContext.getContentResolver(),  
      Settings.System.SCREEN_BRIGHTNESS,  );  

      brightness

2.public static void doCmds(List<String> cmds) throws Exception { 
    Process process = Runtime.getRuntime().exec("su"); 
    DataOutputStream os = new DataOutputStream(process.getOutputStream()); 
 
    for (String tmpCmd : cmds) { 
            os.writeBytes(tmpCmd+"\n"); 
    } 
 
    os.writeBytes("exit\n"); 
    os.flush(); 
    os.close(); 
 
    process.waitFor(); 
}