Java Tutorial

Creating a complete guide for all these topics is quite extensive, as each topic involves detailed concepts, explanations, and examples. Below, I’ll outline a high-level structure with concise details on each topic. If you’d like, we can delve deeper into any specific area with examples.

Java Basics

1. Java Output: System.out.println() is used for displaying output. It prints with a newline, while System.out.print() does not.

   System.out.println("Hello, World!");
   

2. Java Comments:

   • Single-line: // This is a comment
   • Multi-line: /* This is a multi-line comment */

3. Java Variables: Store values with types like int, double, String.

   int age = 25;
   String name = "John";
   

4. Java Data Types: Primitive types (int, float, boolean, etc.) and non-primitive types (String, arrays).

5. Java Type Casting: Converting one type to another, e.g., int to double.

   int a = 5;
   double b = (double) a;
   

6. Java Operators: Arithmetic (+, -), relational (==, !=), logical (&&, ||), etc.

Java Control Structures

7. Java If…Else: Conditional statements.

   if (age > 18) {
       System.out.println("Adult");
   } else {
       System.out.println("Minor");
   }
   

8. Java Switch: Selective execution based on values.

   switch (day) {
       case 1: System.out.println("Monday"); break;
       default: System.out.println("Unknown day");
   }
   

9. Java Loops:

   • While Loop: Repeats while a condition is true.
   • For Loop: Iterates a set number of times.

   for (int i = 0; i < 5; i++) {
       System.out.println(i);
   }
   

10. Java Break/Continue: Control loop execution; break exits a loop, and continue skips to the next iteration.

Java Data Structures

11. Java Arrays: Fixed-size collection of elements.

    int[] numbers = {1, 2, 3};
    

12. Java ArrayList: Resizable array structure.

    ArrayList<String> list = new ArrayList<>();
    list.add("Apple");
    

13. Java HashMap: Key-value pairs for data storage.

    HashMap<String, Integer> map = new HashMap<>();
    map.put("John", 25);
    

14. Java LinkedList: Doubly-linked list.

Java Methods and OOP Concepts

15. Java Methods: Functions defined inside classes.

    public static int sum(int a, int b) {
        return a + b;
    }
    

16. Java Classes/Objects: Define object structure and create instances.

    public class Person {
        String name;
    }
    Person p = new Person();
    

17. Java Constructors: Special methods to initialize objects.

    public Person(String name) {
        this.name = name;
    }
    

18. Java Inheritance: Enables class hierarchy where subclasses inherit from superclasses.

    public class Animal { }
    public class Dog extends Animal { }
    

19. Java Polymorphism: Allows methods to do different things based on context.

20. Java Encapsulation: Hiding data using private variables and public methods.

    private int age;
    public int getAge() { return age; }
    

21. Java Abstraction and Interfaces: Abstract classes and interfaces define methods without implementation.

    interface AnimalActions { void speak(); }
    

22. Java Enums: Define a fixed set of constants.

    enum Days { MONDAY, TUESDAY }
    

Java Collections and Utilities

23. Java Date: Date and time management using java.util.Date and java.time packages.

24. Java Iterator: Traverse collections.

    Iterator<String> it = list.iterator();
    while(it.hasNext()) {
        System.out.println(it.next());
    }
    

25. Java Wrapper Classes: Wrappers for primitive data types (Integer, Double, etc.).

26. Java Exceptions: Handle errors with try, catch, finally.

    try {
        int division = 10 / 0;
    } catch (ArithmeticException e) {
        System.out.println("Cannot divide by zero");
    }
    

27. Java RegEx: Match patterns in strings.

Java Multithreading and Lambda Expressions

28. Java Threads: Concurrent programming using Thread and Runnable.

    class MyThread extends Thread { public void run() { System.out.println("Running"); } }
    

29. Java Lambda: Functional programming with lambda expressions.

    List<Integer> list = Arrays.asList(1, 2, 3);
    list.forEach(n -> System.out.println(n));
    

Java File Handling

30. Java Files: Work with file input/output.

    File file = new File("filename.txt");
    

31. File Create/Write: FileWriter to create and write to files.

    FileWriter writer = new FileWriter("filename.txt");
    writer.write("Hello, World!");
    writer.close();
    

32. File Read/Delete: Read files with Scanner, delete with delete().

Java How-To’s and Basic Operations

33. Add Two Numbers:

    int a = 5, b = 3;
    int sum = a + b;
    

34. Reverse a String:

    String reversed = new StringBuilder("Hello").reverse().toString();
    

35. Sort an Array:

    int[] numbers = {5, 3, 8, 1};
    Arrays.sort(numbers);
    

36. Random Number Generation:

    int randomNum = (int) (Math.random() * 100);