Getting initialization error connecting to Oracle Driver

In my Spring Boot application I updated the application.properties to connect to Oracle DB as :

spring.datasource.url = jdbc:oracle:thin:@//${mysql.service.host}:${mysql.service.port}/${mysql.service.database}
spring.datasource.username = ${mysql.service.username}
spring.datasource.password = ${mysql.service.password}
spring.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver

and included the Oracle Driver dependency in build.gradle file as:

runtime group: 'com.oracle.database.jdbc', name: 'ojdbc11', version:'21.1.0.0'

But still facing error:

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: oracle.jdbc.driver.OracleDriver
    org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650)
20 common frames omitted
Caused by: java.lang.IllegalStateException: Cannot load driver class: oracle.jdbc.driver.OracleDriver
at org.springframework.util.Assert.state(Assert.java:97)
    org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineDriverClassName(DataSourceProperties.java:223)
    org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.initializeDataSourceBuilder(DataSourceProperties.java:175)
    org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration.createDataSource(DataSourceConfiguration.java:43)
at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration$Hikari.dataSource(DataSourceConfiguration.java:85)
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.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)

Any suggestions for the fix please?