Java Spring bean with private constructor

Is possible in Spring that class for bean doesn't have public constructor but only private ? Will this private constructor invoked when bean is created? Thanks.

Yes, Spring can invoke private constructors. If it finds a constructor with the right arguments, regardless of visibility, it will use reflection to set its constructor to be accessible.

You can always use a factory method to create beans rather than relying on a default constructor, from The IoC container: Instantiation using an instance factory method:

<!-- the factory bean, which contains a method called createInstance() -->
<bean id="serviceLocator" class="com.foo.DefaultServiceLocator">
  <!-- inject any dependencies required by this locator bean -->
</bean>

<!-- the bean to be created via the factory bean -->
<bean id="exampleBean"
      factory-bean="serviceLocator"
      factory-method="createInstance"/>

This has the advantage that you can use non-default constructors for your bean, and the dependencies for the factory method bean can be injected as well.