SpringBoot application in Tomcat server: PostgreSQL Driver Not Found - postgresql

Question

I am using Spring boot application to develop Postgresql based application using Eclipse IDE(openjdk version 1.8.0_151)
I have configured gradle as follows:
compile group: 'org.postgresql', name: 'postgresql', version: '42.1.4'
compile group: 'org.springframework.boot', name: 'spring-boot-starter-jdbc'
I am using Spring JdbcTemplate to access database. Everything works perfect in Eclipse IDE. I want to create a war file and deploy into Tomcat 9 server. But unfortunately, I got the following error message:
org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: No suitable driver found for jdbc:postgresql://server:5432/db_pm
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:619)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:684)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:716)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:726)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:776)
at org.springframework.jdbc.core.JdbcTemplate.queryForList(JdbcTemplate.java:853)
at com.kpaudel.pm.PasswordManagerDAO.getSimilarServices(PasswordManagerDAO.java:108)
at com.kpaudel.pm.PasswordManagerDAO$$FastClassBySpringCGLIB$$482fbdc8.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)
at com.kpaudel.pm.PasswordManagerDAO$$EnhancerBySpringCGLIB$$8f3e1618.getSimilarServices(<generated>)
at com.kpaudel.telegram.bots.PasswordManagerBot.onUpdateReceived(PasswordManagerBot.java:87)
at java.util.ArrayList.forEach(ArrayList.java:1255)
at org.telegram.telegrambots.generics.LongPollingBot.onUpdatesReceived(LongPollingBot.java:27)
at org.telegram.telegrambots.updatesreceivers.DefaultBotSession$HandlerThread.run(DefaultBotSession.java:301)
Caused by: java.sql.SQLException: No suitable driver found for jdbc:postgresql://server:5432/db_pm
at java.sql.DriverManager.getConnection(DriverManager.java:689)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriverManager(DriverManagerDataSource.java:153)
at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriver(DriverManagerDataSource.java:144)
at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnectionFromDriver(AbstractDriverBasedDataSource.java:196)
at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnection(AbstractDriverBasedDataSource.java:159)
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
... 19 common frames omitted
I have copied Postgresql driver (postgresql-42.1.4.jar) into $CATALINA_HOME/lib directory also, that also did not help.