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191 Lessons1. Introduction to Java
2. What is Java?
3. History of Java
4. Java Tutorial for Beginners
5. How Do Java Programs Work?
6. JDK in Java
7. C++ Vs Java
8. Java vs. Python
9. Java vs. JavaScript
10. From Java Source Code to Executable
11. How to Install Java in Linux
12. How to Install Java in Windows 10
13. Java Hello World Program
14. Structure of Java Program and Java Syntax
15. Operators in Java
16. Java If-else
17. Switch Case In Java
18. Loops in Java
19. Infinite loop in Java
20. For Loop in Java
21. For Each Loop in Java
22. Constructor in Java
23. Constructor Overloading in Java
24. Copy Constructor in Java
25. Default Constructor in Java
26. Parameterized Constructors in Java
27. Constructor Chaining In Java
28. Finalize Method in Java
29. Static Method in Java
30. Equals Method in Java
31. Abstract Method in Java
32. toString() Method in Java
33. Difference between equals method in Java
34. Inheritance in Java
35. Multiple Inheritance in Java
36. Hierarchical Inheritance in Java
37. Java Classes and Objects
38. Scanner Class in java
39. All classes in java are inherited from which class
40. What is Nested Class in Java
41. POJO Class in Java
42. Anonymous Class in Java
43. Final Class in Java
44. Object Class in Java
45. Packages in Java
46. Access Modifiers in Java
47. Static Keyword In Java
48. Final Keyword in Java
49. Checked and Unchecked Exceptions in Java
50. User Defined Exception in Java
51. Error vs. Exception in Java
52. Java Collection
53. Collections in Java
54. Garbage Collection in Java
55. Generics In Java
56. Java Interfaces
57. Functional Interface in Java
58. Marker Interface in Java
59. Streams in Java
60. Byte stream in java
61. File Handling in Java
62. Thread in Java
63. Thread Lifecycle In Java
64. Daemon Thread in Java
65. Thread Priority in Java
66. Deadlock in Java
67. String Pool in Java
68. Java Database Connectivity(JDBC)
69. Design Patterns in Java
70. Functional Programming in Java
71. OOP vs Functional vs Procedural
72. Heap Memory and Stack Memory in Java
73. Applet in Java
74. Java Swing
75. Java Frameworks
76. Hibernate Framework
77. JUnit Testing
78. How to Install Eclipse IDE for Java?
79. Command line arguments in Java
80. Jar file in Java
81. Java Clean Code
82. OOPs Concepts in Java
83. Java OOPs Concepts
84. Overloading vs Overriding in Java
85. Java 8 features
86. String in Java
87. String to int in Java
88. Why String Is Immutable in Java?
89. Primitive Data Types in Java
90. Non-Primitive Data Types in Java
91. This and Super Keyword in Java
92. HashMap in Java
93. Comparable And Comparator in Java
94. Type Casting in Java
95. Arrays Sort in Java with Examples
96. Variable Hiding and Variable Shadowing in Java
97. Enum in Java
98. Substring in Java
99. Pattern Programs in Java
100. Hashcode in Java
101. What is ByteCode in Java?
102. How To Take Input From User in Java
103. GCD of Two Numbers in Java
104. Linked List in Java
105. Arithmetic Operators in Java
106. Conditional Operators in Java
107. Stack and Queue in Java
108. Array Length in Java
109. Number Pattern Program in Java
110. Split in java
111. Map In Java
112. Difference Between Throw and Throws in Java
113. Difference Between Data Hiding and Abstraction
114. HashSet in Java
115. String Length in Java
116. Factorial Using Recursion in Java
117. DateFormat in Java
118. StringBuilder Class in java
119. Instance variables in Java
120. Java List Size
121. Java APIs
122. Reverse an Array in Java
123. StringBuffer and StringBuilder Difference in Java
124. Java Program to Add Two Numbers
125. String to Array in Java
126. Regular Expressions in Java
127. Identifiers in Java
128. Data Structures in Java
129. Set in Java
130. Pass By Value and Call By Reference in Java
131. Try Catch in Java
132. Bubble Sort in Java
133. Caesar Cipher Program in Java
134. Queue in Java
135. Object Creation in Java
136. Multidimensional Array in Java
137. How to Read a File in Java
138. String Comparison in Java
139. Volatile Keyword in Java
140. Control Statements in Java
141. Jagged Array in Java
142. Two-Dimensional Array in Java
143. Java String Format
144. Replace in Java
145. charAt() in Java
146. CompareTo in Java
147. Matrix Multiplication in Java
148. Static Variable in Java
149. Event Handling in Java
150. parseInt in Java
151. Java ArrayList forEach
152. Abstraction in Java
153. String Input in Java
154. Logical Operators in Java
155. instanceof in Java
156. Math Floor in Java
157. Selection Sort Java
158. int to char in Java
159. Stringtokenizer in java
160. Implementing and Manipulating Abs in Java
161. Char array to string in java
162. Convert Double To String In Java
163. Deque in Java
164. Converting a List to an Array in Java
165. The Max function in java
166. Removing whitespace from string in java
167. String arrays in Java
168. Strings in Java Vs Strings in Cpp
169. Sum of digits of a number in Java
170. Art of Graphical User Interfaces
171. Trim in Java
172. RxJava
173. Recursion in Java
174. HashSet Java
175. Difference Between Java and Python
176. Square Root in Java
177. Reverse A String in Java
178. Even Odd Program in Java
179. Fibonacci Series in Java
180. Prime Number Program in Java
181. Java Program to Print Prime Numbers in a Given Range
182. Java Leap Year Program
183. Swapping of Two Numbers in Java
184. LCM of Two Numbers in Java
185. Math.sqrt() Function in Java
186. Area of Triangle in Java
187. Sort a String In Java
188. Factorial Program in Java
189. Javafx
190. Lambda expression in java
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191. Setup Java Home and IDE on macOS
Lambda expressions in Java have revolutionized the way developers approach functional programming. By providing a concise syntax for writing anonymous functions, lambda expressions enable developers to write more readable and expressive code. This article will delve into the world of lambda expressions in Java, exploring their syntax, applications, advantages, and best practices. From understanding the basics to exploring real-life examples, this comprehensive guide will empower you to leverage the power of lambda expressions and simplify your functional programming journey.
Lambda expressions in Java 8 introduced a powerful tool for functional programming by enabling the representation of anonymous functions as values. They simplify the process of writing code by reducing boilerplate and allowing developers to focus on the core logic of their programs. Let's dive deeper into the key concepts and features of lambda expressions in Java.
A lambda expression is an anonymous function—one without a name. It allows you to treat code as data, making it easier to pass behavior as an argument to methods or store it in variables. Lambda expressions in Java consist of three essential parts: parameters, an arrow token, and a body. Here's an example:
To understand lambda expressions fully, we need to grasp the concept of functional interfaces. A functional interface is an interface that contains a single abstract method and is used as the basis for lambda expressions. It serves as the contract for the behavior passed through the lambda expression. Let's explore this concept further with an example:
The syntax of lambda expressions involves specifying parameters, an arrow token, and a body. Let's break it down with a simple example:
As mentioned earlier, lambda expressions are based on functional interfaces. These serve as the contract for the behavior encapsulated within lambda expressions. Let's explore a few examples of functional interfaces commonly used with lambda expressions:
Before the introduction of lambda expressions in Java 8, achieving similar functionality required using anonymous inner classes.
Example of sorting a list with and without lambda expressions.
Let's explore various examples of using lambda expressions in different scenarios to understand their versatility and power.
Lambda expressions can represent functions with no parameters. Here's an example of a lambda expression representing a simple greeting.
Output:
The code defines a lambda expression assigned to a Runnable variable greet. The lambda expression () -> System.out.println("Hello, world!") prints the message "Hello, world!" to the console.
Lambda expressions can also represent functions with a single parameter. Let's consider an example of squaring a number.
Output:
In the code, a lambda expression is assigned to a Function<Integer, Integer> variable named square. The lambda expression x -> x * x takes an Integer parameter x and returns the square of x by multiplying it with itself.
Lambda expressions can handle functions with multiple parameters. Let's consider an example of adding two numbers.
Output:
The code uses a lambda expression (x, y) -> x + y to add two integers. When the calculate method is called on the Calculator object with values 5 and 3, the lambda expression computes their sum, which is 8.
Lambda expressions can be written with or without the explicit use of the return keyword. The compiler infers the return type based on the context.
Here's an example of a lambda expression that calculates the square of a number.
Output:
The code defines a lambda expression that calculates the square of an integer. By applying the lambda expression to the value 5, the output 25 is obtained.
Lambda expressions are commonly used with foreach loops to iterate over collections. Let's consider an example of printing all elements in a list.
Output:
Lambda expressions can comprise multiple statements within the body. Here's an example of a lambda expression that prints a greeting followed by the name.
Output:
Lambda expressions can be used to simplify the creation of threads. Let's consider an example of creating a new thread using a lambda expression.
Output:
Lambda expressions are commonly used in sorting algorithms. Here's an example of sorting a list of names alphabetically.
Output:
Lambda expressions are often used to filter data in collections based on specific conditions. Let's consider an example of filtering a list of numbers to retrieve only the even ones.
Output:
Lambda expressions can simplify event handling in graphical user interfaces. Here's an example of adding an action listener to a button.
The output for the given code will depend on when the button is clicked. The message "Button clicked!" will be printed on the console when it is done.
Lambda expressions in Java serve various functionalities and enable powerful programming paradigms. Let's explore some of the key functionalities and use cases.
As discussed earlier, the syntax of lambda expressions involves specifying parameters, an arrow token, and a body. The body can comprise a single statement or a block of code.
Lambda expressions can accept zero or more parameters. The parameters define the input values passed to the lambda expression.
Lambda expressions in Java allow us to treat them as objects and can be assigned to variables, passed as arguments, or returned from methods. They provide a powerful and flexible way to encapsulate behavior.
Lambda expressions can access variables from their enclosing scope. These variables can be categorized into local, instance, and static variables.
In Java 8, lambda expressions were introduced as a powerful feature to enhance the functionality of the language. Lambda expressions provide a concise and expressive way to represent anonymous functions or methods. They play a significant role in enabling functional programming paradigms in Java. Let's check the specifics of lambda expressions in Java 8.
Lambda expressions in Java 8 are based on functional interfaces. A functional interface is an interface that contains only one abstract method. The lambda expression provides a compact syntax for implementing the abstract method of a functional interface. This means that lambda expressions can be used wherever a functional interface is expected, making the code more expressive and concise.
The return type of a lambda expression in Java 8 is inferred by the compiler based on the context in which the lambda expression is used. Since functional interfaces have a single abstract method, the compiler can determine the return type based on the method signature defined in the functional interface. The return type is not explicitly specified in the lambda expression itself.
Let's consider an example to understand lambda expressions and their return types in Java 8:
Output:
In the code, a functional interface Calculator is defined with a single abstract method calculate, that takes two integers x and y as parameters and returns an integer.
Lambda expressions offer several advantages in Java programming:
While lambda expressions offer numerous benefits, it's also essential to consider their limitations.
To ensure effective and maintainable code when using lambda expressions, consider the following best practices:
Lambda expressions, also known as arrow functions, are a feature introduced in JavaScript ES6 (ECMAScript 2015) to provide a more concise syntax for writing functions. Lambda expressions in JavaScript allow you to define anonymous functions in a shorter and more expressive way.
Here's an example to demonstrate the usage of lambda expressions in JavaScript.
Output:
In the given code, both the regular function expression and the lambda expression perform the multiplication of two numbers. The regular function multiply uses the return keyword, while the lambda expression multiplyLambda directly returns the multiplication result.
Lambda expressions have transformed the way developers approach functional programming in Java. By providing a concise and expressive syntax, they simplify the process of writing anonymous functions and enhance code readability. With their ability to encapsulate behavior and eliminate boilerplate code, lambda expressions empower developers to write cleaner, more modular, and efficient code. By understanding the syntax, functionalities, and best practices of lambda expressions, you can unlock their full potential and leverage the power of functional programming in Java.
Here are some of the interview questions related to Lambda expressions in Java.
1. How do lambda expressions simplify functional programming in Java?
Lambda expression in Java simplify functional programming by enabling concise and expressive code. They facilitate the representation and passing of behavior as data. They also support functional programming constructs like higher-order functions and functional interfaces, promoting a focus on behavior rather than implementation details.
2. How does a lambda expression differ from a regular method in Java?
Lambda expressions are anonymous functions without formal declarations or separate method bodies. They can be defined inline at the point of use, resulting in more concise code.
3. How are lambda expressions used in JavaScript?
In JavaScript, lambda expressions, also known as arrow functions, provide a concise syntax for function definitions. They are commonly used for shorter function expressions, especially as callbacks or event handlers. Lambda expressions in JavaScript have implicit return statements, automatically returning the result of the expression without requiring an explicit return keyword
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upGrad does not grant credit; credits are granted, accepted or transferred at the sole discretion of the relevant educational institution offering the diploma or degree. We advise you to enquire further regarding the suitability of this program for your academic, professional requirements and job prospects before enr...