• Explain the H2 database.
• Install H2 database on your machine.

The H2 database is an open-source relational database for the Java platform. It requires very little configuration to set up which makes it a great choice for testing apps and for learning concepts without worrying about database specific configurations.

You will usually see two main ways for storing data in H2 databases:

1. In-memory Storage: data is stored in the RAM while H2 is running. All of the data is removed once H2 is closed.
2. Local Drive Storage: data is stored on a local drive such as HDDs, SSDs, SD cards.

In this section, we will install an H2 database and log into it on a browser. The default user name for the database is sa and there is usually no password. If an empty password field doesn’t give you access, try using sa as the password.

First, we need to install and run the H2 local server and then we can use a web browser to access the GUI.

1. Go to the H2 Database homepage.
2. Download the “All Platforms” zip file.
3. Extract the zip file into a directory (usually extracted as an H2 directory).
4. Open a Terminal and navigate to the bin directory in the extracted directory.
5. Add execution permission for the h2.sh file by running chmod +x h2.sh.
6. Run ./h2.sh to start the H2 database.

1. Go to the H2 Database homepage.
2. Download the “All Platforms” zip file.
3. Extract the zip file into a directory (usually extracted as an H2 directory).
4. Navigate to the bin directory in the extracted directory.
5. Run the h2.bat file to start the H2 database.

The above steps should have opened up your web browser on localhost:8082 and show a GUI for logging in. Put sa for the username and keep the password field empty. Click on “connect” to access the database.

Whenever you’re accessing the database in your Java app, make sure that the database is running in the terminal or command line.

In this lesson we have set up and accessed an H2 database. In later lessons we will learn how to configure our Java apps to interact with the database.