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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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Stream API in Java 8: Complete Guide with Examples
Stream api is a powerful abstraction for processing sequence of elements in a functional and declarative style . it allows developers to perform complex data manipulations such as filtering , mapping , sorting and reducing with minimal boilerplate code . Stream represent a pipeline of operations that can be executed either sequentially or in parallel , improving both readability and performance . Purpose of Stream Api The main goals of the stream api are . 1.Simplify data processing: Replace verbose loops with expressive operations 2.Enable Functional programing : use lambda expressions and method references 3. Improve Performance: Support parallel execution with parallel stream . Pipeline in Java Stream A stream…
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Default and Static Methods in Java 8 Interface – Features & Use Cases
A default method is a method define in an interface with a default implementation .it uses the default keyword and allows interfaces to have behavior without forcing all implementing classes to override it . Syntax: The main purpose of default methods is to enable backward combability when evolving interfaces before java8 , adding a new method to an interface would break all implementing classes with default methods, you can add new functionality without affecting existing code . Features of Default Methods in Java Interface with default method Abstract class Use Cases of Default Methods in Java What is Static Method in an Interface A static method in an interface is…
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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…