譬如说我程序中有一个Spring bean如下，它会被一个自定义的Util普通类（里面都是静态方法）所用，

@Component
public class SpringContextUtil implements ApplicationContextAware {

    private static ApplicationContext context = null;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext)
        throws BeansException {
    this.context = applicationContext;
    }

    public static <T> T getBean(String beanName) {
        return (T) context.getBean(beanName);
    }

    public static String getActiveProfile() {
        return context.getEnvironment().getActiveProfiles()[0];
    }
}

那假如这个Spring Bean在Util类初始化后再初始化肯定不行，那么像这种问题，spring是如何解决的？譬如Util类对Spring Bean的SpringContextUtil.getActiveProfile()的调用会触发该bean的初始化？或者因为该bean未初始化，只是SpringContextUtil类加载了，然后因为applicationContext未注入，导致Null pointer Exception?