static final String LOGINURL     = "https://login.salesforce.com";
static final String GRANTSERVICE = "/services/oauth2/tokengrant_type=password";
private static final String CLIENTID = "*******";
private static final String CLIENTSECRET = "----25284058416";
private static final String USERID = "****userID.com";
private static final String PASSWORD = "*****"; //password + securityToken

private static final String ACCESSTOKEN = "access_token";
private static final String INSTANCEURL = "instance_url";
private static String instanceUrl;
private static Header oAuthHeader;

public static void main(String[] args) {
HttpClient httpclient = HttpClientBuilder.create().build();

   String loginURL = LOGINURL +
                      GRANTSERVICE +
                      "&client_id=" + CLIENTID +
                      "&client_secret=" + CLIENTSECRET +
                      "&username=" + USERID +
                      "&password=" + PASSWORD;

    HttpPost httpPost = new HttpPost(loginURL);
    HttpResponse httpResponse = null;

    try {
        httpResponse = httpclient.execute(httpPost);
    } catch (ClientProtocolException clientProtocolException) {
        clientProtocolException.printStackTrace();
    } catch (IOException ioException) {
                    ioException.printStackTrace();
    } catch (Exception exception) {
        exception.printStackTrace();
    }

    final int statusCode = httpResponse.getStatusLine().getStatusCode();
    if (statusCode != HttpStatus.SC_OK) {
        System.out.println("Error:  " + statusCode + "tt "+ httpResponse.getStatusLine().getReasonPhrase());
        System.out.println("Error authenticating to Salesforce.com platform: " + statusCode);
        return;
    }

    String httpMessage = null;
    try {
        httpMessage = EntityUtils.toString(httpResponse.getEntity());
    } catch (IOException ioException) {
        ioException.printStackTrace();
    }

    JSONObject jsonObject = null;
    String accessToken = null;
    try {
        jsonObject = (JSONObject) new JSONTokener(httpMessage).nextValue();
        accessToken = jsonObject.getString(ACCESSTOKEN);
        instanceUrl = jsonObject.getString(INSTANCEURL);
    } catch (JSONException jsonException) {
        jsonException.printStackTrace();
    }

    //oAuthHeader = new BasicHeader("Authorization", "OAuth2 " + accessToken);
    httpPost.releaseConnection();
}