Hikari. The number of ActiveConnections is increasing - oracle

Question

I am using Hikari and connecting to Oracle.
As i understand, connections should be closed by try-block automatically. But unfortunately, after each call the ActiveConnections increases. When it reaches 100 i get exception:
java.sql.SQLTransientConnectionException: HikariPool-2 - Connection is
not available, request timed out after 10001ms.
[jconsole helps me to see the value of ActiveConnections][1]
application.properties:
spring.datasource.hikari.register-mbeans = true
spring.datasource.hikari.driver-class-name = oracle.jdbc.pool.OracleDataSource
spring.datasource.hikari.connection-timeout=10000
spring.datasource.hikari.idle-timeout=10000
spring.datasource.hikari.max-lifetime=30000
spring.datasource.hikari.maximum-pool-size=100
spring.datasource.hikari.minimum-idle=5
spring.datasource.hikari.auto-commit=false
Java class:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
#Autowired
private JdbcTemplate jdbcTemplate;
#Transactional
public String getFormButtons() {
try (
OracleConnection conn = jdbcTemplate.getDataSource().getConnection()
.unwrap( OracleConnection.class );
)
{
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
...
}
Key dependencies in pom.xml:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>com.zaxxer</groupId>
<artifactId>HikariCP</artifactId>
<version>4.0.3</version>
</dependency>
<dependency>
<groupId>com.oracle.database.jdbc</groupId>
<artifactId>ojdbc8</artifactId>
<version>19.8.0.0</version>
<type>jar</type>
</dependency>
Please explain me what wrong is.
UPD.
I have made some corrections:
changed
spring.datasource.hikari.driver-class-name = oracle.jdbc.pool.OracleDataSource to
spring.datasource.hikari.driver-class-name = oracle.jdbc.OracleDriver.
removed artifact #Transaction;
used HikariDataSource instead of jdbcTemplate.getDataSource():
#Autowired
private HikariDataSource hds;
Despite this, after each call the number of ActiveConnections still increases.

Answer 1

I have found the solution to my issue. In short, I abandoned try-with-resource statement and managed connection closure by myself.