String DB_CONNECTION_STR = "jdbc:hsqldb:mem:MySpecialTestDb";
String DB_USERNAME_STR = "sa";
String DB_USERNAME_PASSWORD = "";
DriverManager.getConnection(DB_CONNECTION_STR, DB_USERNAME_STR, DB_USERNAME_PASSWORD);

String DB_CONNECTION_STR = "jdbc:hsqldb:mem:AnotherTestDb";
String DB_USERNAME_STR = "sa"; // could use different here, doesn't matter
String DB_USERNAME_PASSWORD = "";
DriverManager.getConnection(DB_CONNECTION_STR, DB_USERNAME_STR, DB_USERNAME_PASSWORD);