How to Free host java servlet/jsp website using postgres database on heroku App cloud

1.  Download the Heroku Commandline Interface from  below link:
https://s3.amazonaws.com/assets.heroku.com/heroku-toolbelt/heroku-toolbelt.exe
now install it with simple steps next next only.

Create account on Heroku with below signup link .
https://signup.heroku.com/dc

Login to Heroku Cloud
Create a Procfile
You declare how you want your application executed in Procfile in the project root. Create this file with a single line:

web:    java $JAVA_OPTS -jar target/dependency/webapp-runner.jar --port $PORT target/*.war

Commit your changes to Git:
$ git init
$ git add .
$ git commit -m "Ready to deploy"

Create the app:
$ heroku create
Creating high-lightning-129... done, stack is cedar-14
http://high-lightning-129.herokuapp.com/ | git@heroku.com:high-lightning-129.git
Git remote heroku added

Deploy your code:
$ git push heroku master
The application is now deployed. Ensure that at least one instance of the app is running:
$ heroku ps:scale web=1

Congratulations! Your web app should now be up and running on Heroku. Open it in your browser with:
$ heroku open
Git Cloning Existing Heroku Applications
heroku git:clone -a myapp
Replace myapp with the name of your app.
Complete Reference on:

Connect To Database on Heroku
1. create Database
 c:\> heroku addons:create heroku-postgresql:hobby-dev

2. Know all details about data plan
heroku pg:info
3 heroku pg:credential
4. Maven add this to your pom.xml:

<dependency>
  <groupId>org.postgresql</groupId>
  <artifactId>postgresql</artifactId>
  <version>9.4.1208</version>
</dependency>

5. connect to database using java

private static Connection getConnection() throws URISyntaxException, SQLException {
    String dbUrl = System.getenv("JDBC_DATABASE_URL");
    return DriverManager.getConnection(dbUrl);
}

OR

Create a JDBC connection to Heroku Postgres by parsing the DATABASE_URL environment variable.

private static Connection getConnection() throws URISyntaxException, SQLException {
    URI dbUri = new URI(System.getenv("DATABASE_URL"));

    String username = dbUri.getUserInfo().split(":")[0];
    String password = dbUri.getUserInfo().split(":")[1];
    String dbUrl = "jdbc:postgresql://" + dbUri.getHost() + ':' + dbUri.getPort() + dbUri.getPath();

    return DriverManager.getConnection(dbUrl, username, password);
}


Sharing Heroku Postgres between applications
You can share one Heroku Postgres between multiple applications.
 heroku addons:attach webapp1616::DATABASE --app myweb2016