The Complete Core Java Course : Learn to Code

Explore basic string operations in Java, including creating strings, concatenation with + and concat, length and index concepts, trim, converting strings to uppercase or lowercase, plus empty checks.

Explore string comparison in Java by using equals, equals ignore case, compareTo, and matches with regex to validate outputs in testing.

Learn how to use contains, starts with, and ends with to locate substrings; explore index of, last index of, and case handling with lowercase conversions.

Explore string cut operations in Java, including character access by index, handling out-of-bounds exceptions, substring with begin and end indices, reversing with a for loop, and splitting by a delimiter.

Learn to replace characters and strings in Java using replace and replace all with regular expressions. Replace matches and remove special characters, as shown, 1234 becomes I.

Learn how to convert an integer to a normal string, binary, hex, and octal representations, and how to convert those strings back to integers using the appropriate radix.

Define a class as a template with variables and methods, then instantiate objects with new, using the constructor to set each object; create multiple objects with independent state.

Define an employee class with name, id, and salary fields and a method to compute a 20% bonus. Create employee main class, instantiate two objects, assign values, and display bonuses.

Explore methods in Java through creating basic methods, methods with arguments, and methods that return values; learn object creation, calling methods, and using them across classes.

Explore method overloading in Java by using the same method name with different argument types, counts, or orders, and learn how Java selects the correct method.

Explore access specifiers in Java, including public, default, private, and protected access, and learn how package scope and inheritance influence visibility.

Understand how constructors initialize object state, including default and explicit constructors, this keyword, and constructor overloading illustrated by a road toll example.

Explore data encapsulation or data hiding in Java, using private fields and getters and setters to control indirect access in object-oriented programming.

Explore the static keyword in Java, showing how static fields and methods belong to the class rather than objects, enabling shared values and class-based access.

Learn that the public static void main method is the Java program’s entry point, and the JVM provides the runtime environment while string args and no such method error matter.

Learn to build a bank account class using class and object concepts, with private fields, a constructor to initialize account details, plus deposit, withdraw, and balance display methods.

Explore Java's math class in java.lang package, using methods for min, max, pow, sqrt, and constants like PI and E, with sin, cos, tan, log, ceil, floor, round, and random.

Learn how the StringBuilder class in Java creates mutable strings to avoid creating new string objects during repeated concatenation, improving memory and performance; explore append, delete, and reverse methods.

Explore string builder methods such as insert, replace, delete, and reverse through practical examples, including inserting at a specific index, replacing a character range, and reversing the string.

Explore how to use the scanner class to capture user input in java, including strings with nextLine and numbers with nextInt or nextDouble, and reverse a string with a loop.

Generate random numbers in Java using the Random class from java.util, producing 100 values in ranges such as 0 to 1000 and 1000 to 10000, with nextInt.

Generate universally unique identifiers in Java using the UUID class. Display ten UUID.randomUUID values in a loop as 128-bit alphanumeric identifiers.

Learn how the var keyword enables type inference for local variables in Java 10. Understand limits like no class level use, no array initializers with var, and no parameters.

Learn how the Java 10 garbage collector interface simplifies adding or removing garbage collectors and improves garbage collection performance within the JVM's memory management.

Discover Java 10 updates: object heap allocation to user-specified memory with DRAM, six-month releases, and default root certificates enabling TLS for OpenJDK builds.

Learn how inheritance enables a child class to reuse fields and methods from a parent class through extends, creating an is-a relationship in examples like polygon, triangle, and rectangle.

Explore method overriding in inheritance by comparing it with overloading, using Animal, Dog, and Cat examples where Dog and Cat override the parent method to print their identity.

Explore polymorphism in Java by showing how an object can take multiple forms, such as animal, dog, and cat, via a single reference and overriding methods.

Explore the super keyword to access methods and fields from a superclass, illustrate method overriding, and call parent class code from subclass using super.doThis and super.num1.

explains how the super keyword calls the parent constructor when a subclass is created, showing how to pass arguments, handle no-argument constructors, and ensure proper initialization.

Explore protected access in Java, compare it with public, default, and private, and see how inheritance and package scope affect visibility of fields like make and model.

Explore abstraction as the fourth pillar of object-oriented programming in Java, learning how to hide implementation details using abstract classes and abstract methods, and using interfaces as an alternative.

unlock how java interfaces define abstract methods, how classes implement them, how interfaces extend others for multiple inheritance, and that interfaces cannot be instantiated, including static and default methods.

Learn how the final keyword makes fields constants, prevents method overriding, and forbids inheritance for classes in Java, with examples of final fields, methods, and classes.

Master arrays in Java by learning how to declare and populate arrays of strings, integers, and characters, access elements via 0-based indices, update values, and iterate with for loops.

Declare a fixed length integer array and learn that uninitialized elements default to zero, then update specific positions; also create fixed length string and character arrays.

Explore the enhanced for loop (for-each) in Java to iterate over arrays and collections like array lists and linked lists, with a practical example generating a multiplication table.

Learn to reverse an array by swapping start and end elements with a for loop from index 0 to mid, using a temp variable; a common interview question.

Explore how a 2-dimensional array in Java is an array of arrays with rows of varying lengths. Learn to declare, access, update, and iterate its elements using nested for loops.

Create a 2-D array to hold the multiplication tables from 2 to 6, fill with i*j using nested loops, and print each table on its own line.

Explore how a Java array of objects holds heterogeneous data types, including strings, numbers, and chars, and extend to two-dimensional arrays for tabular data, with iteration and printing for testing.

Explore ArrayList in Java, a dynamic array that implements the List interface, and master its core operations: add, get, set, remove, clear, contains, sub list, size, toArray, isEmpty, and iteration.

Explore the structure of doubly linked lists, where each element contains previous, next, and data, connected through pointers from head to tail, not stored contiguously.

Explore linked list basics in Java: a LinkedList implements the List interface, links elements with pointers, and offers add, get, set, remove, clear, contains, indexOf, lastIndexOf, and peek/poll methods.

Compare ArrayList and LinkedList by their internal structures—dynamic array versus doubly linked list—and note faster access in ArrayList and quicker insertions and deletions in LinkedList.

Learn to use a ListIterator to traverse a list forward or backward and modify elements, such as removing nulls, replacing nulls with 0, and converting odd numbers to even.

Explore how hash sets in Java prevent duplicates and do not guarantee insertion order or positional access. Learn union, intersection, and converting a set to a list.

Learn how the linked hash set, an ordered version of the hash set, preserves insertion order, disallows duplicates, supports add, remove, clear, contains, size, and can convert to a list.

Explore how TreeSet offers a sorted ascending collection unlike HashSet, with add, remove, clear, contains, and easy conversion to list.

Iterate over sets using a modified for loop or an iterator, compare hash set’s lack of order with tree set’s ascending sorting.

Learn how Java hash maps store key-value pairs, add via put, retrieve with get, check keys with containsKey, and extract keySet, values, and entries.

Explore how a tree map uses a red-black tree to sort entries by ascending keys and apply common methods like put, get, contains value, and replace, plus poll first/last entries.

Learn to iterate over maps in Java by converting a map to an entry set and using a for-each loop or an iterator, with a tree map example.

Explore regular expressions in Java, learning to define patterns to extract digits, remove non-digits, and use meta characters and quantifiers to build flexible regex patterns.

Explore quantifiers in regular expressions, including asterisk, plus, and question mark, and learn how curly brackets set exact, minimum, or maximum repetitions with grouping and the matches method.

Explore character classes in regular expressions, including digits, word characters, whitespace, their opposites, with examples like phone numbers and area codes, learning escaping with double backslashes and 2-9 quantifiers.

Explore bracket expressions in RegEx, using square brackets to match one of multiple characters, including ranges, the not sign, and literals, and quantifiers allow repetition.

Demonstrate how the or operator uses the pipe symbol to specify one option from a group. Explore patterns like ab, ac, ad, xyz, or 123, and why acd is invalid.

Explore how the dot operator matches any single character, how dot plus asterisk forms greedy matches, and the basics of greedy versus non-greedy quantifiers.

Master greedy and lazy (non-greedy) matching in Java regex using quantifiers like *, +, and {min,max}, and learn to capture text between x and y with Pattern and Matcher.

Create a regular expression to match four example websites using a group and the pipe for alternation, with escapes to treat dots as literals.

Learn to regularize and extract prices with a regex pattern matching a dollar amount with decimals, using pattern and matcher to print all matches like 24.99 and 0.00.

Master regex to regularize number ranges with digit blocks, optional digits, and the or operator. Build patterns for 0 to 99, 0 to 1000.