Learnitweb

Author: Editorial Team

  • SessionFactory vs. Session in Hibernate

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    1. What is SessionFactory? Hibernate is a powerful Object-Relational Mapping (ORM) framework for Java that simplifies database interactions. At its core, two crucial interfaces, SessionFactory and Session, are fundamental to its operation. Understanding their roles and differences is key to effectively using Hibernate. 1.1 Understanding SessionFactory The SessionFactory in Hibernate is a heavyweight, thread-safe object…

  • Error boundary in React functional component

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    React does not allow you to catch render-time errors inside functional components without using a class-based component. This is because: Only class components can implement componentDidCatch and getDerivedStateFromError, which are required to catch rendering errors in React. Why You Can’t Build a Purely Functional Error Boundary Today React’s error boundary mechanism is built around lifecycle…

  • Differences between get() and load() in Hibernate

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    Differences Aspect get() load() Retrieval Strategy Eager loading (hits the database immediately) Lazy loading (returns a proxy and hits DB only when needed) When is the DB hit? Immediately when get() is called Only when you access a non-identifier property (lazy init) Return type Actual object or null Proxy object (subclass proxy) What if object…

  • Insert Interval Problem

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    1. Problem Statement You are given a list of non-overlapping intervals sorted by their start time. You are also given a new interval that needs to be inserted into the list. Insert the new interval such that the list remains sorted and non-overlapping. If necessary, merge overlapping intervals. Constraints The list is already sorted by…

  • React.FC

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    What is React.FC? React.FC (or React.FunctionComponent) is a TypeScript type used to define functional components in React. It helps you add type safety to your props, making your components more predictable and easier to maintain. Basic Syntax Here: Advantages of React.FC Drawbacks of React.FC Alternative (Manual Function Typing) Instead of React.FC, you can also define…

  • What Happens if You Run a Rolling Deploy with a Bad Config?

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    In Kubernetes, a Rolling Update is the default deployment strategy used to update applications without downtime. However, if the update includes a bad configuration—such as an incorrect environment variable, bad image, broken readiness probe, or wrong secret—it can partially or completely break your application. 1. What Is a Rolling Deployment? A Rolling Deployment in Kubernetes…

  • What Happens if etcd Fails in Kubernetes?

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    In Kubernetes, etcd is a distributed key-value store that acts as the brain of the cluster. It stores all cluster data—including node information, Pod definitions, ConfigMaps, Secrets, and more. If etcd fails, the entire Kubernetes control plane is affected. 1. What is etcd? etcd is a high-availability, strongly consistent, distributed key-value store built on the…

  • What Happens When an Unready Pod Gets Traffic?

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    In Kubernetes, Pod readiness is crucial in determining whether a Pod should receive traffic from Services. Kubernetes uses readiness probes to decide if a Pod is ready to serve requests. But what if a Pod is unready and still receives traffic? 1. What Does “Unready” Mean? A Pod is marked “Ready” when: Readiness Probe Example:…

  • What Happens If the Service Selector Doesn’t Match Any Pods?

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    1. Introduction In Kubernetes, a Service is used to expose one or more Pods under a single IP address and DNS name. This is made possible through a selector, which connects the Service to the appropriate Pods by matching their labels. But what if the selector doesn’t match any pods? This situation is quite common…

  • What Happens if a Node Runs Out of Memory in Kubernetes?

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    1. Introduction In a Kubernetes cluster, a node is a worker machine (virtual or physical) that runs containerized workloads. Each node has finite resources—CPU, memory, disk, and network bandwidth. If a node runs out of memory, Kubernetes and the underlying OS (typically Linux) must respond immediately to prevent system crashes. 2. What is Memory Pressure?…