title: Caused by: java.lang.IllegalArgumentException: Property 'driverClassName' must not be empty
body: <p>In the code I have shared here <a href="https://stackoverflow.com/questions/62238830/exception-in-thread-restartedmain-java-lang-reflect-invocationtargetexception">Exception in thread &quot;restartedMain&quot; java.lang.reflect.InvocationTargetException Caused by: java.lang.NullPointerException</a> I am getting new error. Could you please help me with this.</p>
  
  <pre><code>org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'springLogging3Application': Unsatisfied dependency expressed through field 'factory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'factory' defined in com.spring.main.SpringLogging3Application: Unsatisfied dependency expressed through method 'getSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'datasource' defined in com.spring.main.SpringLogging3Application: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Circular reference involving containing bean 'springLogging3Application' - consider declaring the factory method as static for independence from its containing instance. Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalArgumentException: Property 'driverClassName' must not be empty
      at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:598) ~[spring-beans-5.1.15.RELEASE.jar:5.1.15.RELEASE]
  Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Circular reference involving containing bean 'springLogging3Application' - consider declaring the factory method as static for independence from its containing instance. Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalArgumentException: Property 'driverClassName' must not be empty
      at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.1.15.RELEASE.jar:5.1.15.RELEASE]
      at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:622) ~[spring-beans-5.1.15.RELEASE.jar:5.1.15.RELEASE]
      ... 51 common frames omitted
  Caused by: java.lang.IllegalArgumentException: Property 'driverClassName' must not be empty
      at org.springframework.util.Assert.hasText(Assert.java:284) ~[spring-core-5.1.15.RELEASE.jar:5.1.15.RELEASE]
  </code></pre>
  
  <p>application.properties</p>
  
  <pre><code>server.port=6565
  
  db.driver:oracle.jdbc.driver.OracleDriver
  db.url:jdbc:oracle:thin:@localhost:1521:xe  
  db.username:xxxx  
  db.password:xxxx
  
  hibarenate.dialect:org.hibernate.dialect.OracleDialect
  hibarenate.show_sql:true  
  hibarenate.hbm2ddl.auto:update
  entitymanager.packagesToScan:com.spring.main
  </code></pre>
  
  <p>Updated one:</p>
  
  <pre><code>server.port=6565
  
  db.driver=oracle.jdbc.driver.OracleDriver
  db.url=jdbc:oracle:thin:@localhost:1521:xe  
  db.username=xxxx 
  db.password=xxxx
  
  hibarenate.dialect=org.hibernate.dialect.OracleDialect
  hibarenate.show_sql=true  
  hibarenate.hbm2ddl.auto=update
  entitymanager.packagesToScan=com.spring.main
  </code></pre>