public class HibernateUtil {

private static SessionFactory sessionFactory;

static {
    try {
        Class.forName("com.mysql.jdbc.Driver");
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }
    Configuration cnf = new Configuration();

    // Properties
    cnf.setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver");
    cnf.setProperty("hibernate.connection.url", "jdbc:mysql://localhost:3306/test_db?useSSL=false‌​");
    cnf.setProperty("hibernate.connection.username", "root");
    cnf.setProperty("hibernate.connection.password", "root");
    cnf.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
    cnf.setProperty("hibernate.hbm2ddl.auto", "update");
    cnf.setProperty("hibernate.show_sql", "true");
    cnf.setProperty(" hibernate.connection.pool_size", "1");

    StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder()
            .applySettings(cnf.getProperties());
    sessionFactory = cnf.buildSessionFactory(builder.build());

    // Class mappings
}

public static SessionFactory getSessionFactory(){
    return sessionFactory;
}
}

Exception in thread "main" java.lang.ExceptionInInitializerError
at core.Tester.main(Tester.java:10)
Caused by: org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:271)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:691)
at database.HibernateUtil.<clinit>(HibernateUtil.java:34)
... 1 more
Caused by: org.hibernate.exception.JDBCConnectionException: Error calling Driver#connect
at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator$1$1.convert(BasicConnectionCreator.java:105)
at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.convertSqlException(BasicConnectionCreator.java:123)
at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:41)
at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
at org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:123)
at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:42)
at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:20)
at org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:161)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:109)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:72)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:259)
... 14 more
Caused by: java.sql.SQLException: The connection property 'useSSL' only accepts values of the form: 'true', 'false', 'yes' or 'no'. The value 'false‌​' is not in this set.
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
at com.mysql.jdbc.ConnectionPropertiesImpl$ConnectionProperty.validateStringValues(ConnectionPropertiesImpl.java:314)
at com.mysql.jdbc.ConnectionPropertiesImpl$BooleanConnectionProperty.initializeFrom(ConnectionPropertiesImpl.java:91)
at com.mysql.jdbc.ConnectionPropertiesImpl$ConnectionProperty.initializeFrom(ConnectionPropertiesImpl.java:216)
at com.mysql.jdbc.ConnectionPropertiesImpl.initializeProperties(ConnectionPropertiesImpl.java:2503)
at com.mysql.jdbc.ConnectionImpl.initializeDriverProperties(ConnectionImpl.java:3153)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:774)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:38)
... 29 more