Q:

Error creating bean with name 'transactionManager': Cannot resolve reference to bean ''sessionFactory'' while setting bean property 'sessionFactory'

i'm with this error and i can't find the solution
I'm using postgres with Grails
Here's the error that keeps occurring
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManagerPostProcessor': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Invocation of init method failed; nested exception is org.hibernate.MappingException: Could not instantiate id generator [entity-name=beans.AbsPessoa]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:207)
    at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:687)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:523)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766)
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307)
    at grails.boot.GrailsApp.run(GrailsApp.groovy:55)
    at grails.boot.GrailsApp.run(GrailsApp.groovy:374)
    at grails.boot.GrailsApp.run(GrailsApp.groovy:363)
    at grails.boot.GrailsApp$run.call(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:133)
    at trabalhoestagio.Application.main(Application.groovy:8)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Invocation of init method failed; nested exception is org.hibernate.MappingException: Could not instantiate id generator [entity-name=beans.AbsPessoa]
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1481)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1226)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.grails.transaction.TransactionManagerPostProcessor.initialize(TransactionManagerPostProcessor.java:75)
    at org.grails.transaction.TransactionManagerPostProcessor.setBeanFactory(TransactionManagerPostProcessor.java:53)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeAwareMethods(AbstractAutowireCapableBeanFactory.java:1597)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1565)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
    ... 20 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Invocation of init method failed; nested exception is org.hibernate.MappingException: Could not instantiate id generator [entity-name=beans.AbsPessoa]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
    ... 34 common frames omitted
Caused by: org.hibernate.MappingException: Could not instantiate id generator [entity-name=beans.AbsPessoa]
    at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.createIdentifierGenerator(DefaultIdentifierGeneratorFactory.java:123)
    at org.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:225)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:323)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1859)
    at org.grails.orm.hibernate.cfg.HibernateMappingContextConfiguration.buildSessionFactory(HibernateMappingContextConfiguration.java:196)
    at org.grails.orm.hibernate.HibernateMappingContextSessionFactoryBean.doBuildSessionFactory(HibernateMappingContextSessionFactoryBean.java:476)
    at org.grails.orm.hibernate.HibernateMappingContextSessionFactoryBean.buildSessionFactory(HibernateMappingContextSessionFactoryBean.java:470)
    at org.grails.orm.hibernate.HibernateMappingContextSessionFactoryBean.afterPropertiesSet(HibernateMappingContextSessionFactoryBean.java:93)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
    ... 41 common frames omitted
Caused by: java.lang.ClassCastException: org.grails.config.NavigableMap$NullSafeNavigator cannot be cast to java.lang.Boolean
    at net.kaleidos.hibernate.PostgresqlExtensionsDialect$TableNameSequenceGenerator.configure(PostgresqlExtensionsDialect.java:60)
    at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.createIdentifierGenerator(DefaultIdentifierGeneratorFactory.java:117)

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':bootRun'.
> Process 'command 'C:\Program Files\Java\jdk1.8.0_91\bin\java.exe'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
    ... 50 common frames omitted
Error |
Failed to start server (Use --stacktrace to see the full trace)

Here's my build.gladle
buildscript {
    ext {
        grailsVersion = project.grailsVersion
    }
    repositories {
        mavenLocal()
        maven { url "https://repo.grails.org/grails/core" }
    }
    dependencies {
        classpath "org.grails:grails-gradle-plugin:$grailsVersion"
        classpath "com.bertramlabs.plugins:asset-pipeline-gradle:2.8.2"
        classpath "org.grails.plugins:hibernate4:5.0.5"
    }
}

version "0.1"
group "trabalhoestagio"

apply plugin:"eclipse"
apply plugin:"idea"
apply plugin:"war"
apply plugin:"org.grails.grails-web"
apply plugin:"org.grails.grails-gsp"
apply plugin:"asset-pipeline"

ext {
    grailsVersion = project.grailsVersion
    gradleWrapperVersion = project.gradleWrapperVersion
}

repositories {
    jcenter()
    mavenLocal()
    maven { url "https://repo.grails.org/grails/core" }
}

dependencyManagement {
    imports {
        mavenBom "org.grails:grails-bom:$grailsVersion"
    }
    applyMavenExclusions false
}

dependencies {    
    compile "org.springframework.boot:spring-boot-starter-logging"
    compile "org.springframework.boot:spring-boot-autoconfigure"
    compile "org.grails:grails-core"
    compile "org.springframework.boot:spring-boot-starter-actuator"
    compile "org.springframework.boot:spring-boot-starter-tomcat"
    compile "org.grails:grails-dependencies"
    compile "org.grails:grails-web-boot"
    compile "org.grails.plugins:cache"
    compile "org.grails.plugins:scaffolding"
    compile "org.grails.plugins:hibernate4"
    compile "org.hibernate:hibernate-ehcache"
    console "org.grails:grails-console"
    profile "org.grails.profiles:web:3.1.6"
    runtime "com.bertramlabs.plugins:asset-pipeline-grails:2.8.2"
    runtime "com.h2database:h2"
    testCompile "org.grails:grails-plugin-testing"
    testCompile "org.grails.plugins:geb"
    testRuntime "org.seleniumhq.selenium:selenium-htmlunit-driver:2.47.1"
    testRuntime "net.sourceforge.htmlunit:htmlunit:2.18"
    compile 'org.grails.plugins:postgresql-extensions:4.6.1'
    provided 'org.postgresql:postgresql:9.4-1203-jdbc4'
}

task wrapper(type: Wrapper) {
    gradleVersion = gradleWrapperVersion
}

assets {
    minifyJs = true
    minifyCss = true
}

And this is my Application.yml
 hibernate:
        dialect: net.kaleidos.hibernate.PostgresqlExtensionsDialect
        cache:
            queries: false
            use_second_level_cache: true
            use_query_cache: false
            region.factory_class: 'org.hibernate.cache.ehcache.EhCacheRegionFactory'

    dataSource:
        pooled: true
        jmxExport: true
        driverClassName: org.postgresql.Driver
        username: postgres
        password: password
        url: jdbc:postgresql://localhost:5432/trabalho
        dbCreate: update

    environments:
        development:
            dataSource:
                dbCreate: create-drop
                url: jdbc:postgresql://localhost:5432/trabalho
        test:
            dataSource:
                dbCreate: update
                url: jdbc:postgresql://localhost:5432/trabalho
        production:
            dataSource:
                dbCreate: update
                url: jdbc:postgresql://localhost:5432/trabalho
                properties:
                    jmxEnabled: true
                    initialSize: 5
                    maxActive: 50
                    minIdle: 5
                    maxIdle: 25
                    maxWait: 10000
                    maxAge: 600000
                    timeBetweenEvictionRunsMillis: 5000
                    minEvictableIdleTimeMillis: 60000
                    validationQuery: SELECT 1
                    validationQueryTimeout: 3
                    validationInterval: 15000
                    testOnBorrow: true
                    testWhileIdle: true
                    testOnReturn: false
                    jdbcInterceptors: ConnectionState
                    defaultTransactionIsolation: 2 # TRANSACTION_READ_COMMITTED

    ---
    ---
    grails:
        profile: web
        codegen:
            defaultPackage: trabalhoestagio
        spring:
            transactionManagement:
                proxies: false
    info:
        app:
            name: '@info.app.name@'
            version: '@info.app.version@'
            grailsVersion: '@info.app.grailsVersion@'
    spring:

        groovy:
            template:
                check-template-location: false

    ---
    grails:
        mime:
            disable:
                accept:
                    header:
                        userAgents:
                            - Gecko
                            - WebKit
                            - Presto
                            - Trident
            types:
                all: '*/*'
                atom: application/atom+xml
                css: text/css
                csv: text/csv
                form: application/x-www-form-urlencoded
                html:
                  - text/html
                  - application/xhtml+xml
                js: text/javascript
                json:
                  - application/json
                  - text/json
                multipartForm: multipart/form-data
                pdf: application/pdf
                rss: application/rss+xml
                text: text/plain
                hal:
                  - application/hal+json
                  - application/hal+xml
                xml:
                  - text/xml
                  - application/xml
        urlmapping:
            cache:
                maxsize: 1000
        controllers:
            defaultScope: singleton
        converters:
            encoding: UTF-8
        views:
            default:
                codec: html
            gsp:
                encoding: UTF-8
                htmlcodec: xml
                codecs:
                    expression: html
                    scriptlets: html
                    taglib: none
                    staticparts: none
    endpoints:
        jmx:
            unique-names: true

A:

From your log: 
Caused by: java.lang.ClassCastException: org.grails.config.NavigableMap$NullSafeNavigator..... 

seems related to: grails-postgresql-extensions plugin
According to:
https://github.com/kaleidos/grails-postgresql-extensions/issues/84
problem was fixed in version: 4.6.5 and you are using: 4.6.1
Hope it helps

