Java - H2 in-memory database even if I use DB_CLOSE_DELAY=-1 reports Table not found

I'm using h2 database as dependency for maven project:

 <dependency>           <groupId>com.h2database</groupId>           <artifactId>h2</artifactId>           <version>1.4.200</version>   </dependency>  

To use in-memory mode I've configured application.properties file:

jdbc:h2:mem:test;DB_CLOSE_DELAY=-1  

as mentioned here and here, because for variant: jdbc:h2:mem:test .

the content of the database is lost at the moment the last connection is closed.

At the same time, I've configured Data Sources using Intelij Idea:

Next step, I've successfully filled data using the script w/ h2-dialect:

CREATE TABLE users  (      id    int NOT NULL GENERATED BY DEFAULT AS IDENTITY,      login varchar(10),      PRIMARY KEY (id),      UNIQUE (login)  );  CREATE TABLE teams  (      id   int NOT NULL GENERATED BY DEFAULT AS IDENTITY,      name varchar(10),      PRIMARY KEY (id)  );  CREATE TABLE users_teams  (      user_id int,      team_id int,      FOREIGN KEY (user_id)          REFERENCES users (id) ON DELETE CASCADE,      FOREIGN KEY (team_id)          REFERENCES teams (id) ON DELETE CASCADE,      UNIQUE (              user_id,              team_id          )  );  

after filling the connection wasn't closed, but I'm still getting the error if I run the program during the connection:

jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager insertUser  Table "USERS" not found; SQL statement:  INSERT INTO users (login) VALUES ('petrov'); [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager insertUser  Table "USERS" not found; SQL statement:  INSERT INTO users (login) VALUES ('obama'); [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager findAllUsers  Table "USERS" not found; SQL statement:  SELECT * FROM users; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager insertTeam  Table "TEAMS" not found; SQL statement:  INSERT INTO teams (name) VALUES ('teamB'); [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager insertTeam  Table "TEAMS" not found; SQL statement:  INSERT INTO teams (name) VALUES ('teamC'); [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager findAllTeams  Table "TEAMS" not found; SQL statement:  SELECT * FROM teams; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager getUser  Table "USERS" not found; SQL statement:  SELECT * FROM users WHERE users.login='petrov'; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager getUser  Table "USERS" not found; SQL statement:  SELECT * FROM users WHERE users.login='ivanov'; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager getUser  Table "USERS" not found; SQL statement:  SELECT * FROM users WHERE users.login='obama'; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager returnTeam  Table "TEAMS" not found; SQL statement:  SELECT * FROM teams WHERE teams.name='teamA'; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager returnTeam  Table "TEAMS" not found; SQL statement:  SELECT * FROM teams WHERE teams.name='teamB'; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager returnTeam  Table "TEAMS" not found; SQL statement:  SELECT * FROM teams WHERE teams.name='teamC'; [42102-200]  jan 19, 2021 3:50:01 AM com.epam.rd.java.basic.practice8.db.DBManager findAllUsers  Table "USERS" not found; SQL statement:  SELECT * FROM users; [42102-200]  Exception in thread "main" java.lang.NullPointerException  ===========================  ===========================  ===========================      at com.epam.rd.java.basic.practice8.Demo.main(Demo.java:382)  

Also I've tried to use:

jdbc:h2:mem:test;IFEXISTS=FALSE  

as stated here, but the same issue during the connection.

Logic for Demo class looks like:

public class Demo {        private static <T> void printList(List<T> list) {          for (T element : list) {              System.out.println(element);          }      }        public static void main(String[] args) {            DBManager dbManager = DBManager.getInstance();            dbManager.insertUser(User.createUser("petrov"));          dbManager.insertUser(User.createUser("obama"));            printList(dbManager.findAllUsers());            System.out.println("===========================");            dbManager.insertTeam(Team.createTeam("teamB"));          dbManager.insertTeam(Team.createTeam("teamC"));            printList(dbManager.findAllTeams());            System.out.println("===========================");            User userPetrov = dbManager.getUser("petrov");          User userIvanov = dbManager.getUser("ivanov");          User userObama = dbManager.getUser("obama");            Team teamA = dbManager.getTeam("teamA");          Team teamB = dbManager.getTeam("teamB");          Team teamC = dbManager.getTeam("teamC");            dbManager.setTeamsForUser(userIvanov, teamA);          dbManager.setTeamsForUser(userPetrov, teamA, teamB);          dbManager.setTeamsForUser(userObama, teamA, teamB, teamC);            for (User user : dbManager.findAllUsers()) {              printList(dbManager.getUserTeams(user));              System.out.println("~~~~~");          }            System.out.println("===========================");            dbManager.deleteTeam(teamA);            teamC.setName("teamX");          dbManager.updateTeam(teamC);            printList(dbManager.findAllTeams());      }  }  

Can someone explain me, please, why this error appears if:

By default, closing the last connection to a database closes the database. For an in-memory database, this means the content is lost. To keep the database open, add ;DB_CLOSE_DELAY=-1 to the database URL. To keep the content of an in-memory database as long as the virtual machine is alive, use jdbc:h2:mem:test;DB_CLOSE_DELAY=-1.

https://stackoverflow.com/questions/65784609/java-h2-in-memory-database-even-if-i-use-db-close-delay-1-reports-table-not-f January 19, 2021 at 10:11AM