NullPointerException at org.jasypt.encryption.simpleConfig.getPasswordCharArray

Question

I am fairly new to spring-maven environment and have a question about dependencies.

applicationContext.xml

    <bean id="configurationEncryptor" class="org.jasypt.encryption.pbe.StandardPBEStringEncryptor">
        <property name="config" ref="environmentVariablesConfiguration" />
    </bean>
    <bean id="environmentVariablesConfiguration" class="com.jpmc.security.jasypt.EnvironmentStringPBEConfig">
        <property name="algorithm" value="SOME_VALUE" />
        <property name="provider">
           <bean class="org.bouncycastle.jce.provider.BouncyCastleProvider" />
        </property> 
    </bean>

Stack Trace:

java.lang.NullPointerException
    at org.jasypt.encryption.pbe.config.SimplePBEConfig.getPasswordCharArray(SimplePBEConfig.java:434)
    at org.jasypt.encryption.pbe.StandardPBEByteEncryptor.resolveConfigurationPassword(StandardPBEByteEncryptor.java:740)
    at org.jasypt.encryption.pbe.StandardPBEByteEncryptor.initialize(StandardPBEByteEncryptor.java:590)
    at org.jasypt.encryption.pbe.StandardPBEStringEncryptor.initialize(StandardPBEStringEncryptor.java:553)
    at org.jasypt.encryption.pbe.StandardPBEStringEncryptor.decrypt(StandardPBEStringEncryptor.java:705)
    at org.jasypt.properties.PropertyValueEncryptionUtils.decrypt(PropertyValueEncryptionUtils.java:72)
    at org.jasypt.spring.properties.EncryptablePropertyPlaceholderConfigurer.convertPropertyValue(EncryptablePropertyPlaceholderConfigurer.java:111)
    at org.springframework.beans.factory.config.PropertyResourceConfigurer.convertProperty(PropertyResourceConfigurer.java:123)
    at org.springframework.beans.factory.config.PropertyResourceConfigurer.convertProperties(PropertyResourceConfigurer.java:106)
    at org.springframework.beans.factory.config.PropertyResourceConfigurer.postProcessBeanFactory(PropertyResourceConfigurer.java:83)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:284)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:166)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:678)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:520)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4939)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:656)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1635)
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

After seeing the trace, I guessed the reason as the lack of value in the property tag of name="provider". But later, I learnt that the value is injected by a different class which initiliazes the provider property. can someone help me understand what exactly is happpening here? I thought the property can be initiliazed like this: <property name="password" value="123" />

Please let me know if any furhter information is needed.