Tutorial Playlist
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
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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
191. Setup Java Home and IDE on macOS
The Java "Hello, World!" program holds immense significance for those taking initial steps into the programming world. It serves as a fundamental starting point, acquainting individuals with the language and illustrating the core principles of writing, compiling, and executing Java code.
This tutorial teaches you how to use the System.out.println() method to display the iconic "Hello, World!" message on the console. This program acts as a stepping stone, facilitating comprehension of Java's syntax, variables, and basic program structure. It presents a straightforward yet impactful approach to gaining hands-on experience and fostering self-assurance in Java coding.
The class definition plays a vital role in the Java "Hello, World!" program. It serves as a blueprint or template that specifies the structure and behavior of objects in Java. The class acts as a container, holding relevant data and methods.
In the "Hello, World!" program, the class definition commences with the keyword "class," followed by the class name. It encapsulates the necessary code for program execution. Within the "Hello, World!" program's class definition, you'll find the main method, which acts as the starting point for program execution.
Syntax:
public class HelloWorld {
//rest of the program or the main() method
}
The main() method is a crucial component in Java programs. It serves as the entry point for the program, meaning that the Java Virtual Machine (JVM) starts executing the program from this method. In the case of the “Hello, World!” program, we use the System.out.println() statement inside the main method to print the string "Hello, World!" to the console.
Syntax:
public static void main(String[] args) {
System.out.println("Hello, World!");
}
To create a Java Hello World example, you only need a few basic components, making it an ideal starting point for beginners. By fulfilling these requirements, you can easily run a Java Hello World program and observe the "Hello, World!" message appearing on the console. The requirements include the following:
Let us break down each portion of the code to understand how this program is created:
public class HelloWorld: This line defines a class named HelloWorld. The class is declared public, which means it can be accessed from other classes. The name of the class must match the name of the Java file it is defined in.
public static void main(String[] args): This is the main method declaration. It is declared public, which allows it to be accessed from anywhere. It is also declared static, meaning it belongs to the class itself and can be invoked without creating an instance of the class. The void keyword indicates that the main method does not return any value.
The main method takes a single parameter of type String array (String[] args). This parameter allows the program to receive command-line arguments when the program is run. The args parameter can be used to access and process the command-line arguments within the main method.
System.out.println("Hello, World!");: This line uses the System.out.println statement to print the string "Hello, World!" to the console. The System.out is a reference to the standard output stream, and println is a method that prints a line of text. The text enclosed in double quotes is the content to be printed.
Java programs use various parameters to ensure their proper functioning. You can successfully create and execute your initial Java program by using these parameters effectively.
The "class" keyword defines a class in Java, which acts as a blueprint for objects.
The "public" modifier allows access to the class by other classes and packages.
The "static" keyword denotes a method or variable as a class-level entity, enabling access without creating an instance of the class.
"Void" signifies that the main method does not return any value.
The "main" method serves as the starting point of execution for the Java program.
It is a parameter of the main method that allows command-line arguments to be passed to the program.
This statement outputs text to the console, printing the specified message enclosed in parentheses.
A Java program can be written in multiple ways using various methods. Let us check out other alternative methods for writing the “Hello World” program using different techniques and methods.
public class HelloWorld {
public static void main(String[] args) {
if (args.length > 0) {
System.out.println("Hello, " + args[0] + "!");
} else {
System.out.println("Hello, World!");
}
}
}
Inside the main method of this example, there is an if statement that checks whether any command-line arguments are present. It does this by checking the length of the args array. A length greater than zero (args.length > 0) implies there are arguments.
If there are command-line arguments, the code executes the block of code within the if statement. It uses the System.out.println statement to print "Hello, " concatenated with the first argument (args[0]), followed by an exclamation mark. This creates a customized greeting message based on the provided argument.
The code executes the code block within the else statement if no command-line arguments are provided. It uses the System.out.println statement to print the default greeting "Hello, World!" to the console.
public class HelloWorld {
public static void main(String[] args) {
System.out.print("Hello, World!");
}
}
In this alternative, we use System.out.print instead of System.out.println to print "Hello, World!" without appending a newline character. The output would be "Hello, World!" displayed on the console without a line break.
public class HelloWorld {
public static void main(String[] args) {
System.out.printf("Hello, %s!", "World");
}
}
In this alternative, we use System.out.printf method to format and print the string. The %s is a placeholder for a string value, and "World" is passed as an argument to replace the placeholder. The output would be "Hello, World!" displayed on the console.
The error message "javac is not recognized as an internal or external command" typically indicates that the Java compiler (javac) is not properly set up or the system environment variables are not configured correctly. To resolve this error, you can try out these steps:
To compile the program, you must first name the .java file correctly, depending on what you decide to name your public class. If you do not name the file correctly, you will face an error such as this:
You can run the program once you are ready with the code and the HelloWorld.java file. Once you run the program in the IDE you are using, the program will begin compiling and finally generate the output.
The Java "Hello, World!" program is the foundation for beginners venturing into the programming world. By mastering this program's basic syntax and structure, you gain a solid starting point for your journey in Java development. With its simplicity and clarity, the "Hello, World!" program instills confidence and introduces you to fundamental coding concepts.
From here, you can expand your knowledge and explore the vast possibilities of Java programming. If the Java "Hello, World!" program interests you, consider taking up a professional course offered by upGrad to upgrade your knowledge in this field.
1. Can the displayed message in the Java hello world program be modified?
Yes. You can change the text within the System.out.println() statement to customize the output message.
2. Why is the Java hello world program often recommended as the first program?
The Java hello world program is an introductory exercise because it familiarizes beginners with essential syntax and structure, enabling them to grasp the fundamentals of writing, compiling, and executing a basic program.
3. Is the Java hello world program relevant only for beginners?
Although the Java hello world program is typically associated with beginners, its principles are fundamental in advanced Java programming. Mastering these basics is vital for developing advanced applications.
PAVAN VADAPALLI
Director of Engineering
Director of Engineering @ upGrad. Motivated to leverage technology to solve problems. Seasoned leader for startups and fast moving orgs. Working …Read More
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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...