2025 Core JAVA Bootcamp from Zero to Hero

Master Java control statements, focusing on conditional statements, including if and if-else, with syntax, flow of execution, and examples that show true and false conditions.

Learn how nested if statements and the else‑if ladder handle multi‑way condition checks, ensuring only one block executes and producing outputs such as less than 100 or greater than 50.

Learn how the switch statement in java matches an expression to case values, executes the corresponding block, and falls through without breaks, resorting to the default when no match.

Learn the for loop in Java, detailing initialization, condition, and update steps, with examples of finite and infinite loops and array traversal.

Learn the while loop syntax with initialization, a conditional expression, and an update step, see how the loop prints values and how while true creates an infinite loop.

Explore the do-while loop as an exit-control construct that executes the block first, then checks the condition, printing ten down to two before termination.

Learn how to check whether a given number is a palindrome in Java by reversing digits with a loop, using a scanner input, and comparing with the original.

The lecture explains recursion in Java as a function calling itself, with a base condition to terminate and a recursive call, illustrated by summing numbers up to n.

Implement factorial in java using recursion, featuring a recursive fact(n) method and a main that reads input with scanner and prints the result.

Learn factorial calculation in java using recursion, tracing a recursive fact(n) call from user input to the base case. The process returns 120 for n = 5.

Implement a recursion-based fibonacci sequence in Java with a fib(n) method, base cases fib(0)=0 and fib(1)=1, and fib(n)=fib(n-1)+fib(n-2). Prompt for input using Scanner and print the result.

Explore the fibonacci series via recursion, using fib(n-1) + fib(n-2) with base cases fib(0)=0 and fib(1)=1, tracing input n=4 to a result of 3.

Demonstrate gcd using recursion by guiding input of two numbers, then compute gcd(num2, num1 mod num2) until a zero remainder returns the result, illustrated with 625 and 125.

Reverse a given number using recursion by extracting digits with modulo ten and dividing by ten, printing each digit until the number becomes zero.

The string buffer class is mutable, unlike string. Create objects with or without initial content and with specific capacity; perform append, insert, and delete operations to modify the buffer.

Explore the string buffer class in Java, practicing replace, reverse, length, and toString methods, plus indexOf and lastIndexOf for locating substrings.

Learn how to use the string class charAt method to obtain a character at a specific index, using s.charAt(index) on the string 'Window'.

Learn how the compareTo method compares two strings, returning zero, positive, or negative values; discover its case sensitive behavior and the compareToIgnoreCase variant for case-insensitive comparisons.

Demonstrate string concatenation in Java by using the concat method and the + operator to join word parts and a number, building a final result string.

Learn how the string class equals method returns a boolean by comparing two strings, emphasizing case sensitivity with examples like Hello vs hello.

Explore the string class's equals ignore case method, a case-insensitive string comparison that returns a boolean true or false and differs from the equals method.

The getChars method copies characters from a string into a destination char array from a starting index to the ending index minus one; for 'batman', 3 to 5 yields 'man'.

Demonstrate the length method in the string class, returning the number of characters as an integer, with a practical example of computing and printing a string's length.

Learn to use the replace method in strings to substitute characters, illustrated by replacing all l characters with w in the word hello, and understanding the syntax and output.

Explore how the split method divides a string into smaller parts using a delimiter such as space or comma. See a Java example that splits a sentence into tokens.

Learn how to use the split method in Java to divide a string by spaces, store the results in s, and print each part with a loop.

Learn how to compare strings in Java by avoiding relational operators and using the equals method. The lecture contrasts == with equals and explains string pool effects.

Explain how the substring method in strings extracts a portion of a string by index, copying characters into a new string, with examples using word.substring(i, k) and word.substring(i).

Learn how to use the toLowerCase and toUpperCase methods on strings to convert all characters to lowercase or uppercase, with practical examples and syntax.

Learn how the trim method removes leading and trailing white spaces from strings, using word.trim() to show the result, while internal spaces remain intact.

Count the number of vowels and consonants in a string by converting it to lowercase, looping through characters with a for loop, and printing the counts.

Explore object oriented programming basics, including objects and classes, object creation with new, and core concepts like abstraction, encapsulation, inheritance, and polymorphism with Java examples.

Define a student class with id and name fields, create an object, print them to view default 0 and null, then initialize with a constructor and a parameterized constructor.

Create a rectangle class with length and breadth, initialize them with an insert method, and compute area as length times breadth for two rectangles using a parameterized constructor.

Demonstrate a Java student class constructor that initializes the student name with this, and access it via getName() or direct field access.

This lecture explains inheritance using the extends keyword, showing how a child class inherits methods and variables from a parent class, can override methods, and access parent features through objects.

Explore the four inheritance types in Java—single level inheritance, multilevel inheritance, hierarchical inheritance, and the reason why multiple inheritance is not supported—through simple class examples.

Define a maximum class with two findMax methods of the same name but different parameter counts, returning the maximum value among two or three numbers.

Learn method overriding with a parent and child class, where the child overrides the parent’s display method under inheritance, demonstrating which method prints when called.

Explore how the super keyword lets a subclass access superclass variables and methods, invoke superclass constructors, and reveal default constructor behavior through practical Java examples.

Demonstrates protected versus private specifiers, showing how protected members are accessible from a subclass while private members are not, with a superclass Axis and subclass example revealing access errors.

Explore how the final class in Java prevents inheritance, showing that a final class cannot be extended and its methods cannot be inherited, with examples using parent and child classes.

Java final methods prevent overriding, enabling inline replacement of method bodies and faster execution for improved performance in typical Java applications.

Explore abstract classes and abstract methods in Java, illustrating how a single abstract calculate method can have multiple implementations across subclasses (square, square root, cube).

Explore abstract classes and abstract methods through a car example, detailing a concrete open tank method and overridden steering and brakes in Model T and Sandro, demonstrated via polymorphism.

Explore abstract classes and abstract methods using shape, rectangle, and triangle implementations, illustrating polymorphism with a shape reference calling subclass draw methods. Contrast an abstract game with a stop method.

Explain the syntax of interfaces, including accessibility, name, return types, parameters, and final variables. Demonstrate implementing interfaces with classes, and partial implementations using abstract classes for callbacks and greetings.

See how interfaces define connect and disconnect, implemented by Oracle, and how an activities interface guides Animal through eat, sleep, run, and walk, including abstract class considerations.

Master extending interfaces in Java by creating an activity interface and a joy interface that extends it, then implementing and calling eat, sleep, play, and coding in a class.

Learn how to declare and implement a nested interface inside a class or another interface, access it as ClassName.InterfaceName, and implement isNotNegative to return true for non-negative values.

Explore how Java packages organize directories into built-in and user-defined namespaces, use import statements to access classes, and implement packages with examples like pack, addition, and subtraction.

Define Balance class in package my pack with name and balance fields and a show method; in main method, create three Balance objects and print their names and balances.

Define an interface inside a package, implement it in a class, import it, and call the show data method from main to display data.

Learn to create a sub package inside a main package using the syntax package main.sub, and import a sub package's classes and interfaces in Java.

Explore array class methods: sort for the full array or a subarray, binary search on sorted data (returns index or -1), and utilities like copy, fill, and equals.

Copy elements from a source array into a new target array using a for loop that iterates over the source length, then display the copied array contents.

Create an ArrayList of strings, add fruit names (mango, apple, banana, cherry, grapes), and print the list to show elements in their original order.

Learn how to iterate an ArrayList of strings in Java using an iterator and a for-each loop, including how to add fruits and print each element.

Learn how to work with ArrayList in Java: determine size with size, store in an int, print element count, add colors, and remove elements by index or by value.

Learn how to use the get and set methods on an ArrayList in Java to access and update elements by index, demonstrated with a fruit list.

Learn how to sort a list of strings in Java using Collections.sort, display the list before and after sorting, and understand alphabetical ordering of elements.

Create an integer array list, add sample marks, print the list before sorting, sort the list using Collections.sort, and print the values in ascending order.

Discover the linked list class in Java, create a string list, and navigate head and node structure. Implement add, remove, get, set, and size operations, plus index lookups.

Learn the Java vector class, its synchronization versus ArrayList, and key methods like add, get, remove, size, and contains, with a practical example filling a vector from an array.

Learn to implement a Java stack for integers, perform push and pop operations, check emptiness, peak the top element, and search for an element’s position (returns -1 if not found).

Learn the hash map class by storing key-value pairs and using put, get, remove, clear, and size, and the is empty method, with key set and values views.