Spring – java.io.IOException: Invalid keystore format Spring Security SAML Extension

I have successfully gotten the Spring Security SAML Extension sample application to run. Now, I'm trying to integrate it into my main application. Before I tried to integrate with my application, I created a sample application to integrate it with and it works fine. In my sample application, I used the keystore from downloaded sample application. Now, I'm trying to use the same keystore and I'm getting the following error:

Caused by: org.springframework.beans.factory.BeanCreationException:
Could not autowire method: public void
org.springframework.security.saml.metadata.MetadataGenerator.setKeyManager(org.springframework.security.saml.key.KeyManager);
nested exception is
org.springframework.beans.factory.BeanCreationException: Error
creating bean with name 'keyManager' defined in ServletContext
resource [/WEB-INF/spring/securityContext.xml]: Instantiation of bean
failed; nested exception is
org.springframework.beans.BeanInstantiationException: Could not
instantiate bean class
[org.springframework.security.saml.key.JKSKeyManager]: Constructor
threw exception; nested exception is java.lang.RuntimeException: Error
initializing keystore at
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:596)
at
org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
… 89 more Caused by:
org.springframework.beans.factory.BeanCreationException: Error
creating bean with name 'keyManager' defined in ServletContext
resource [/WEB-INF/spring/securityContext.xml]: Instantiation of bean
failed; nested exception is
org.springframework.beans.BeanInstantiationException: Could not
instantiate bean class
[org.springframework.security.saml.key.JKSKeyManager]: Constructor
threw exception; nested exception is java.lang.RuntimeException: Error
initializing keystore at
org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:278)
at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1114)
at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1017)
at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at
org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
at
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at
org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1017)
at
org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:960)
at
org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:858)
at
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:553)
… 91 more Caused by:
org.springframework.beans.BeanInstantiationException: Could not
instantiate bean class
[org.springframework.security.saml.key.JKSKeyManager]: Constructor
threw exception; nested exception is java.lang.RuntimeException: Error
initializing keystore at
org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:164)
at
org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:125)
at
org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:270)
… 103 more Caused by: java.lang.RuntimeException: Error
initializing keystore at
org.springframework.security.saml.key.JKSKeyManager.initialize(JKSKeyManager.java:121)
at
org.springframework.security.saml.key.JKSKeyManager.(JKSKeyManager.java:79)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method) at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at
org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
… 105 more Caused by: java.io.IOException: Invalid keystore format
at
sun.security.provider.JavaKeyStore.engineLoad(JavaKeyStore.java:650)
at
sun.security.provider.JavaKeyStore$JKS.engineLoad(JavaKeyStore.java:55)
at java.security.KeyStore.load(KeyStore.java:1214) at
org.springframework.security.saml.key.JKSKeyManager.initialize(JKSKeyManager.java:117)
… 111 more

Here is the bean configuration for the JKSKeyManager:

<bean id="keyManager" class="org.springframework.security.saml.key.JKSKeyManager">
        <constructor-arg value="classpath:security/samlKeystore.jks" />
        <constructor-arg type="java.lang.String" value="nalle123" />
        <constructor-arg>
            <map>
                <entry key="apollo" value="nalle123" />
            </map>
        </constructor-arg>
        <constructor-arg type="java.lang.String" value="apollo" />
    </bean>

Can anyone help me with what's causing this error?