How to catch error when app run or program carsh

Hi guys here I have one doubt how can I Catch error when user run app

However how can i get error

  • How to get error

  • How to display in Activity

        try {
        //code that may crash
    } catch(Exception _e){
        //here do something when try detects error
        Log.e("try/catch error", _e.toString());

What is _e