Failure while connecting Spring Boot to PostgreSql database using JPA/Hibernate - postgresql

Question

I am trying to access a PostgreSQL DB from Spring-Boot application using JPA/Hibernate
The Spring-Boot application consists of a RestController which on user events on certain URL, will connect to PostgreSQL DB and add an entry in DB.
To communicate with the PostgreSQL DB, the RestController uses a Spring service instance, whose class autowires a JPARepository.
For the PostgreSQL DB, I have defined a DBConfig class which is annotated with Spring #Configuration and has a createDataSource() method (see below).
I have not defined any DBConnection class as #Configuration OR haven't specified any JDBC connection as #Bean in my DBConfig class because I am assuming that adding #Configuration to the DBConfig will add the connection configuration in Spring ApplicationContext using the application.properties file under classpath.
Do I need to define a separate connection bean inside the DBConfig class? OR
Do I need to define a DBConnection class separately?
Do I need to define connection properties both at DataSource.setJdbcUrl(String) and src/main/resources/application.properties or any one of the two?
Do I need to add any extra dependency other than the ones already listed below in pom.xml?
How to specify and create the connection to PostgreSQL DB from Spring-Boot?
Am I missing any configuration here? (as I am new to Spring JPA/Hibernate)
DBConfig class
import javax.sql.DataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.mchange.v2.c3p0.ComboPooledDataSource;
#Configuration
public class DBConfig {
#Bean
public DataSource createDataSource() throws Exception {
ComboPooledDataSource ds = new ComboPooledDataSource();
ds.setJdbcUrl("jdbc:postgresql://localhost:5432/my_db?user=postgres_user&password=password");
ds.setDriverClass("org.postgresql.Driver");
return ds;
}
}
It is a Spring Service class, with the autowired repository instance to deal with the PostgreSQL DB
ServiceImpl class with JPARepository Instance (autowired)
#Service("webhookService")
public class MyServiceImpl implements MyService {
private static final Logger log = LoggerFactory.getLogger(MyServiceImpl.class);
#Autowired
private MyRepository myRepository;
//methods for dealing with DB e.g. find, add, delete, update, etc.
}
My Spring-Boot RestController class
#RestController
public class MyController {
private static final Logger log = LoggerFactory.getLogger(MyController.class);
#Autowired
MyService myService;
src/main/resources/application.properties
#Datasource properties
spring.datasource.url=jdbc:postgresql://localhost:5432/my_db
spring.datasource.username=postgres_user
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=create-drop
#Hibernate properties
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.generate-ddl=true
Spring-Boot-data / JPA / PostgreSQL dependencies (from pom.xml)
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.5.2</version>
</dependency>
<dependency>
<groupId>com.mchange</groupId>
<artifactId>mchange-commons-java</artifactId>
<version>0.2.11</version>
</dependency>
<dependency>
<groupId>postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>9.1-901-1.jdbc4</version>
<scope>runtime</scope>
</dependency>
Error Stacktrace while deploying .WAR on Tomcat
2017-12-28 11:25:56.281 WARN 3101 --- [HelperThread-#0] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask#1d7cb052 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
org.postgresql.util.PSQLException: This ResultSet is closed.
at org.postgresql.jdbc2.AbstractJdbc2ResultSet.checkClosed(AbstractJdbc2ResultSet.java:2654) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2ResultSet.setFetchSize(AbstractJdbc2ResultSet.java:1771) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc4.Jdbc4Statement.createResultSet(Jdbc4Statement.java:39) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement$StatementResultHandler.handleResultRows(AbstractJdbc2Statement.java:211) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1773) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:512) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:374) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Connection.execSQLUpdate(AbstractJdbc2Connection.java:263) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Connection.getTransactionIsolation(AbstractJdbc2Connection.java:775) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at com.mchange.v2.c3p0.impl.NewPooledConnection.<init>(NewPooledConnection.java:120) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:181) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11]
2017-12-28 11:25:56.282 WARN 3101 --- [HelperThread-#0] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool#25e78fee is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
2017-12-28 11:25:56.282 WARN 3101 --- [HelperThread-#2] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask#61136ebb -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
org.postgresql.util.PSQLException: This ResultSet is closed.
at org.postgresql.jdbc2.AbstractJdbc2ResultSet.checkClosed(AbstractJdbc2ResultSet.java:2654) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2ResultSet.setFetchSize(AbstractJdbc2ResultSet.java:1771) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc4.Jdbc4Statement.createResultSet(Jdbc4Statement.java:39) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement$StatementResultHandler.handleResultRows(AbstractJdbc2Statement.java:211) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1773) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:512) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:374) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Connection.execSQLUpdate(AbstractJdbc2Connection.java:263) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Connection.getTransactionIsolation(AbstractJdbc2Connection.java:775) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at com.mchange.v2.c3p0.impl.NewPooledConnection.<init>(NewPooledConnection.java:120) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:181) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11]
2017-12-28 11:25:56.293 WARN 3101 --- [HelperThread-#2] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool#25e78fee is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
2017-12-28 11:25:56.311 WARN 3101 --- [ost-startStop-1] o.s.b.a.orm.jpa.DatabaseLookup : Unable to determine jdbc url from datasource
org.springframework.jdbc.support.MetaDataAccessException: Could not get Connection for extracting meta data; nested exception is org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:339) ~[spring-jdbc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:366) ~[spring-jdbc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.DatabaseLookup.getDatabase(DatabaseLookup.java:72) ~[spring-boot-autoconfigure-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.JpaProperties.determineDatabase(JpaProperties.java:139) [spring-boot-autoconfigure-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.jpaVendorAdapter(JpaBaseConfiguration.java:105) [spring-boot-autoconfigure-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration$$EnhancerBySpringCGLIB$$ee7fda69.CGLIB$jpaVendorAdapter$4(<generated>) [spring-boot-autoconfigure-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration$$EnhancerBySpringCGLIB$$ee7fda69$$FastClassBySpringCGLIB$$40f1d36d.invoke(<generated>) [spring-boot-autoconfigure-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) [spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:358) [spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration$$EnhancerBySpringCGLIB$$ee7fda69.jpaVendorAdapter(<generated>) [spring-boot-autoconfigure-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_151]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_151]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_151]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_151]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) [spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1080) [spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:857) [spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) [spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.web.support.SpringBootServletInitializer.run(SpringBootServletInitializer.java:154) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.web.support.SpringBootServletInitializer.createRootApplicationContext(SpringBootServletInitializer.java:134) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.boot.web.support.SpringBootServletInitializer.onStartup(SpringBootServletInitializer.java:87) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE]
at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:169) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5196) [catalina.jar:8.5.24]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) [catalina.jar:8.5.24]
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:752) [catalina.jar:8.5.24]
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728) [catalina.jar:8.5.24]
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734) [catalina.jar:8.5.24]
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:986) [catalina.jar:8.5.24]
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1857) [catalina.jar:8.5.24]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_151]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_151]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_151]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_151]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_151]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_151]
Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80) ~[spring-jdbc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:326) ~[spring-jdbc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
... 74 common frames omitted
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118) ~[mchange-commons-java-0.2.11.jar:0.2.11]
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:692) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111) ~[spring-jdbc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77) ~[spring-jdbc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
... 75 common frames omitted
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1469) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:644) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:554) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutAndMarkConnectionInUse(C3P0PooledConnectionPool.java:758) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:685) ~[c3p0-0.9.5.2.jar:0.9.5.2]
... 78 common frames omitted
Caused by: org.postgresql.util.PSQLException: This ResultSet is closed.
at org.postgresql.jdbc2.AbstractJdbc2ResultSet.checkClosed(AbstractJdbc2ResultSet.java:2654) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2ResultSet.setFetchSize(AbstractJdbc2ResultSet.java:1771) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc4.Jdbc4Statement.createResultSet(Jdbc4Statement.java:39) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement$StatementResultHandler.handleResultRows(AbstractJdbc2Statement.java:211) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1773) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:512) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:374) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Connection.execSQLUpdate(AbstractJdbc2Connection.java:263) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at org.postgresql.jdbc2.AbstractJdbc2Connection.getTransactionIsolation(AbstractJdbc2Connection.java:775) ~[postgresql-9.1-901-1.jdbc4.jar:na]
at com.mchange.v2.c3p0.impl.NewPooledConnection.<init>(NewPooledConnection.java:120) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:181) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2]
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) ~[mchange-commons-java-0.2.11.jar:0.2.11]

Answer 1

You don't need to define a #Configuration or Datasource for your Postgres database. If you are using the spring-boot-starter-data-jpa dependency and the Postgres Java driver is also on your classpath (include it in your pom.xml, Spring will automatically connect your application to your database. So just define the connection string in your application.properties and remove your #Configuration class.
Your Repository can look like the following:
public interface MyRepository extends CrudRepository<YourClass, Long>{
// Spring gives your all the basic CRUD operations per default
}
or if you want to use JpaRepository :
public interface MyRepository extends JpaRepository<YourClass, Long>{
// Spring gives your all the basic database operations per default
}
If you need an example project, have a look at: https://github.com/springframeworkguru/spring-boot-postgress-example/blob/master/pom.xml