Complete Core Java for Testers+Interview Programs

Create your first Java program in Eclipse by setting up a project, adding a package and a class with a main method, then run to print a hello message.

Explore arithmetic, logical, and relational operators in Java, including plus, minus, multiply, divide, remainder, increment, decrement, and comparisons like equals, not equal to, greater than, and less than.

Learn how the while loop repeats statements until a condition fails, compare it with the for loop, and note that the do-while loop runs at least once.

Explore how break exits a loop early when a condition is met, and how continue skips to the next iteration, shaping loop output.

Explore string slice operations in Java, including extracting substrings with begin and end indices, splitting by a delimiter into an array, and retrieving a character by index with charAt.

Learn to perform string replace operations and number-to-string conversions in Java, including replacing substrings, removing spaces, and converting between int, float, and string.

Explore how classes define blueprints and how objects instantiate with state and behavior, using an employee example to show attributes, constructors, the new keyword, and the introduce method.

Explore a bank account class with name, account number, and balance; learn credit and debit methods and display balance, demonstrated with multiple objects.

Explore how Java methods group statements to perform tasks and boost code reusability. Learn method types, including void and return-value methods with arguments, and how to call them on objects.

Explore inheritance in Java by extending a calculator class to inherit data members and methods like add, subtract, multiply, and divide, while understanding access rules between parent and child classes.

Explore method overriding, where a subclass replaces a base class method as shown with vehicle, car, and bike. Learn rules: no overriding static or final methods, and no reducing visibility.

Explore how the super keyword enables calling the parent's methods and accessing variables in Java inheritance, and learn about super constructors and constructor chaining.

Master data abstraction in Java by hiding implementation details and exposing how features are used, including that abstract classes cannot be instantiated and abstract methods must be implemented by subclasses.

Learn to perform date and time operations in Java using LocalDate, LocalTime, and LocalDateTime, including today's values, formatting, creating customized dates with LocalDate.of, and computing differences between dates.

Explore java's math class as a static utility for common calculations, including min, max, pow, sqrt, cbrt, ceil, floor, and round, plus generating random numbers.

Generate random numbers in a range with the Random class in java, using nextInt and an offset to obtain 0–max or 100–1000 ranges.

Explore how arrays hold multiple values of a single data type and have fixed size, with zero-based indexing, for declaring, assigning, and retrieving elements.

Learn the enhanced for loop in Java to retrieve and print array values by declaring a variable of the same type as the array elements and iterating over the array.

Learn to traverse a two dimensional array with a modified for loop and an enhanced for loop, accessing and printing elements row by row.

Understand hash sets, which avoid duplicates and do not preserve insertion order, and perform operations like add, remove, contains, size, clear, and union and intersection, plus converting to lists.

Explore tree sets, where unique elements are stored and retrieved in ascending order. Learn that tree sets disallow duplicates, lack index-based access, and support union and intersection operations.

Learn to retrieve elements from a set using a for loop and an iterator, applying hasNext and next to iterate through all values in a collection.

Explore TreeMap behavior, compare it with HashMap, and see how TreeMap sorts keys in ascending order by default, with examples of first and last entries.

Learn to read data from an Excel file in Java by navigating workbook, sheet, rows, and cells, retrieving string, date, and numeric values through loops.

Learn how to convert Excel data to a 2d object array in Java, handling mixed types, calculating rows and columns, and transferring values for data providers.

Learn how to reverse a string in Java using a for loop and scanner, and explore the StringBuilder reverse method as an alternative.

Program demonstrates how to generate the Fibonacci series in Java by iterating with two variables, starting with zero and one, computing and printing the first ten terms.

Write a program that reads a number and validates if it is prime by testing divisors up to half the value, exiting early when a divisor is found.