Referenced from this article.

Here is source code to check Android device rooted.

   /**    * Checks if the device is rooted.    * @return <code>true</code> if the device is rooted, <code>false</code> otherwise.    */

  publicstaticboolean isRooted(){

    // get from build info     String buildTags = android.os.Build.TAGS;     if(buildTags !=null&& buildTags.contains("test-keys")){       returntrue;     }     // check if /system/app/Superuser.apk is present     try{       File file =newFile("/system/app/Superuser.apk");       if(file.exists()){         returntrue;       }     }catch(Exception e1){       // ignore     }     // try executing commands     return canExecuteCommand("/system/xbin/which su")         || canExecuteCommand("/system/bin/which su")|| canExecuteCommand("which su");   }   // executes a command on the system   privatestaticboolean canExecuteCommand(String command){     boolean executedSuccesfully;     try{       Runtime.getRuntime().exec(command);       executedSuccesfully =true;     }catch(Exception e){       executedSuccesfully =false;     }     return executedSuccesfully;   }