Make JdbcDatabaseContainer#getDriverClassName public

[vpavic]

There are use cases which require configuring the actual JDBC driverClassName on DataSource pool implementation. One such example that I ran into recently is using a HikariCP pool with MySQL 8 Testcontainer (related #736).

This PR changes the visibility of JdbcDatabaseContainer#getDriverClassName method to public. With this change, the driverClassName of the container can be reused when configuring the DataSource, rather than having to manually specify it.

There's an additional commit that adds a test to demonstrate the described problem - without setting driverClassName on HikariConfig this test fails (due to wrong driver being used implicitly) with the following stacktrace:

com.zaxxer.hikari.pool.PoolInitializationException: Exception during pool initialization

	at com.zaxxer.hikari.pool.BaseHikariPool.initializeConnections(BaseHikariPool.java:544)
	at com.zaxxer.hikari.pool.BaseHikariPool.<init>(BaseHikariPool.java:171)
	at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:60)
	at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:48)
	at com.zaxxer.hikari.HikariDataSource.<init>(HikariDataSource.java:80)
	at org.testcontainers.junit.SimpleMySQLTest.performQuery(SimpleMySQLTest.java:139)
	at org.testcontainers.junit.SimpleMySQLTest.testMySQL8(SimpleMySQLTest.java:121)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.sql.SQLException: Unknown system variable 'tx_isolation'
Query is : SELECT @@tx_isolation
	at org.mariadb.jdbc.internal.util.ExceptionMapper.get(ExceptionMapper.java:136)
	at org.mariadb.jdbc.internal.util.ExceptionMapper.throwException(ExceptionMapper.java:69)
	at org.mariadb.jdbc.MariaDbStatement.executeQueryEpilog(MariaDbStatement.java:242)
	at org.mariadb.jdbc.MariaDbStatement.executeInternal(MariaDbStatement.java:270)
	at org.mariadb.jdbc.MariaDbStatement.executeQuery(MariaDbStatement.java:383)
	at org.mariadb.jdbc.MariaDbConnection.getTransactionIsolation(MariaDbConnection.java:767)
	at com.zaxxer.hikari.pool.BaseHikariPool.addConnection(BaseHikariPool.java:446)
	at com.zaxxer.hikari.pool.BaseHikariPool.initializeConnections(BaseHikariPool.java:542)
	... 28 more
Caused by: org.mariadb.jdbc.internal.util.dao.QueryException: Unknown system variable 'tx_isolation'
Query is : SELECT @@tx_isolation
	at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.getResult(AbstractQueryProtocol.java:939)
	at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.executeQuery(AbstractQueryProtocol.java:604)
	at org.mariadb.jdbc.MariaDbStatement.executeInternal(MariaDbStatement.java:261)
	... 32 more

[vpavic]

Also see the remark from the HikariCP's documentation on configuration essentials:

jdbcUrl
This property directs HikariCP to use "DriverManager-based" configuration. We feel that DataSource-based configuration (above) is superior for a variety of reasons (see below), but for many deployments there is little significant difference. When using this property with "old" drivers, you may also need to set the driverClassName property, but try it first without. Note that if this property is used, you may still use DataSource properties to configure your driver and is in fact recommended over driver parameters specified in the URL itself. Default: none

[bsideup]

@vpavic do you have any clue why the tests are failing? o_O

[vpavic]

It could be due to the upgraded MySQL JDBC driver. I'll look into it, wanted to see if the proposed change is OK for you first.

[vpavic]

It was due to the upgraded MySQL JDBC driver. I've just reverted it to originally used 5.1.45 as MySQL 8 appears to work with it just fine and the test now are passing, at least for me locally.

It appears that the new MySQL JDBC driver (8.0.11) is more strict and doesn't like dummy URL elements like ;TEST=TOMCAT_WITH_CLASSNAME which are used throughout the JDBCDriverWithPoolTest.

[kiview]

Thanks, I'll merge it.
We might need to look into the MySQL JDBC driver version 8.0.11 in the future though.