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How to Implement Singleton Design Pattern in Java (Step-by-Step)
What is singleton design pattern A Singleton Pattern says that just “define a class that has only one instance and provides a global point of access to it . If singleton class is loaded by two classloaders, two instance of singleton class will be created, one for each classloaders. Key Concepts 1. Significance of Serialization in Singleton Pattern Serialization in Java means converting an object into a byte stream so it can be: Deserialization is the reverse process (byte stream → object). Even if your class ensures only one instance, deserialization creates a NEW object, which violates the Singleton rule. Example: Singleton Class (Without Protection) 2.TestSingleton.java output false // false…
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Java 8 Interview Questions with Real-Time Examples
Java 8 introduced powerful features like Lambda Expressions, Streams, and Functional Interfaces—but are you truly ready to answer real interview questions?This guide covers the most frequently asked Java 8 interview questions with clear explanations and practical examples to help you crack your next interview with confidence. Program1 : Write a program that, given a list of integers, extracts and returns only the even numbers from the input collection. Program2 : Write a program to Find the maximum number of given list using java8 Program3: Write a program to Find duplicate elements in a list What is Collections.frequency()?. It counts how many times an element (o) appears in a collection (c).frequency()…
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Function Functional Interface in Java 8 – Definition, Syntax & Real-World Use Cases
The Function functional interface is a predefined interface introduced in Java 8 as part of the java.util.function package. It represents a function that accepts one input argument and produces one result. This interface is widely used in lambda expressions, Stream API operations, and functional programming. A key feature of the Function interface is that it enables developers to define reusable transformation logic, where an input object is converted into another form. For example, converting a String into its length, a Student object into a grade, or an entity into a DTO. Function is functional interface that takes one argument and produces a result . Syntax: Program1 : Write a program…
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Functional Programming in Java Using Lambda Expressions
A lambda expression is a short and concise way to represent an anonymous function—a function without a name . Key Features 1.Why Lambda expression required Lambda expression required to enable functional programming ,lambda expression allow you to define small functions without naming them . this is useful when the function is simple and used only once or a few times . Lambda Syntax : 2.Lambda Expression Example Example 1: Addition of Number Without Lambda Expressions With Lambda Expressions Example 2: Find the length of String without Lambda Expressions With Lambda Expression if single statements are there then curly bracket not required , if body contained multiple lines of code then…
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Java 8 Features
Java 8 was introduced to modernize Java by adding functional programming features, improving performance, and making the language more concise, readable, and expressive. It aimed to reduce boilerplate code, improve parallel processing, and enable more declarative coding styles—especially important for handling large data collections and multi-core processors. Lambda Expressions 2. Functional Interfaces 3. Default Method in Interface 4.Static Method in Interface Interface MyInterface { default void show() { System.out.println("Default method"); }} 5. Stream API list.stream().filter(s -> s.startsWith("A")).collect(Collectors.toList()); Intermediate (Non-Terminal) operations Example : Terminal operations 6. Method References 7. Optional Class 8. New Date and Time API (java.time package) Old API problems: New API advantages: 9. Collectors Class Commonly Used Collectors…
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What is application
An application refers to a program or software designed to perform specific tasks for users. Applications can range from simple tools like calculators to complex systems such as enterprise resource management platforms. Types of Applications To develop distributed application we use a language called java and java comes under internet software. Architecture required for development of distributed application , programmer must use a well known Architecture known as client server architecture . 2-Tier Architecture Two tier Architecture it contains client and server side programing . 3-Tier Architecture Three tier architecture it contains client , server program and database software n-Tier Architecture n tire architecture it contains client program , fire wall program(security…