Simple RAW JDBC connect
public static final String JDBC_DRIVER = "org.postgresql.Driver";
public static final String DB_URL = ""; // our DB
public static final String USER = ""; // our USER DB
public static final String PASS = ""; // PASS
You can download DB driver from site database provider, or just use Maven like me
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>42.2.11</version>
</dependency>