How to send Authorization header in Android using Volley library?

1.Try using getBodyContentType()::

     JsonObjectRequest req = new JsonObjectRequest(Request.Method.GET, url,
        null, new Response.Listener<JSONObject>() {

    @Override
    public void onResponse(JSONObject response) {
        Log.d("Response", response.toString());
        pd.dismiss();

        Toast.makeText(MainActivity.this, "" + response.toString(), Toast.LENGTH_SHORT).show();
    }
}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        VolleyLog.d("Error", "Error: " + error.getMessage());
        Toast.makeText(MainActivity.this, "" + error.getMessage(), Toast.LENGTH_SHORT).show();
        pd.dismiss();

    }
}) 
{
     @Override
        public String getBodyContentType() {
            return "application/json; charset=utf-8";
        }

    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        HashMap<String, String> headers = new HashMap<String, String>();
        headers.put("Authorization", "2e96e0a4ff05ba86dc8f778ac49a8dc0");
        return headers;
    }
};

This can be simply achieved by using the getHeaders() thus;

@Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String, String> headerMap = new HashMap<String, String>();
                headerMap.put("Content-Type", "application/json");
                headerMap.put("Authorization", "Bearer " + ACCESS_TOKEN);
                return headerMap;
            }

Try following code:

@Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        String credentials = "username" + ":" + "password";
        String base64EncodedCredentials = Base64.encodeToString(credentials.getBytes(), Base64.NO_WRAP);
        HashMap<String, String> headers = new HashMap<>();
        headers.put("Authorization", "Basic " + base64EncodedCredentials);
        return headers;
    }

StringRequest request = new StringRequest(Request.Method.POST, YourUrl, new Response.Listener<String>() {
    @Override
    public void onResponse(String response) {
        if (!response.equals(null)) {
            Log.e("Your Array Response", response);                    
        } else {
            Log.e("Your Array Response", "Data Null");
        }
    }

}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        Log.e("error is ", "" + error);
    }
}) {    

 //This is for Headers If You Needed
    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        Map<String, String> params = new HashMap<String, String>();
        params.put("Content-Type", "application/json; charset=UTF-8");
        params.put("token", ACCESS_TOKEN);
        return params;
    }

 //Pass Your Parameters here
    @Override
    protected Map<String, String> getParams() {
        Map<String, String> params = new HashMap<String, String>();
        params.put("User", UserName);
        params.put("Pass", PassWord);
        return params;
    }
};
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
queue.add(request);