Programming / Beginner

Java Programming

Learn Java from its runtime model and core syntax through object-oriented design, interfaces, and the exception-handling patterns used in real programs.

▤ 5 modules✓ 5 PDFs✦ 1 researched video lesson

What you’ll learn

Learning objectives

Explain how Java source is compiled and run

Use variables, types, operators, and control flow

Model data with classes, objects, inheritance, and interfaces

Handle exceptional conditions with explicit recovery paths

Video lesson

Learn with Telusko

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Java Tutorial for Beginners | Full Course

Telusko · Chapter list extends to about 6h 40m

Covers: Java setup, variables, loops, classes, objects, inheritance, interfaces, and exception handling

Course roadmap

Learn it in 5 modules

0 of 5 completed

MODULE 01Ready to learn

The Java platform and types

Use primitive types for simple values and reference types for objects. Declare variables with meaningful names, use operators intentionally, and understand that expressions have types and precedence. The compiler catches many type mismatches before execution.

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Key idea

Java source is compiled to bytecode, which a Java Virtual Machine executes. A type defines which values a variable may hold and which operations are valid.

Worked example

A fee estimator reads an integer day count and a decimal daily rate, then computes a total using compatible numeric types.

Try it

Declare fields for a book title, page count, and price; choose appropriate types and explain why.

Suggested check

Use `String` for the title, `int` for a whole page count, and `double` or `BigDecimal` for price depending on precision needs. Currency systems should avoid careless binary floating-point rounding.

MODULE 02Ready to learn

Control flow and methods

Use `if/else` for decisions and `for` or `while` for repetition. Methods should have focused responsibilities. Distinguish a return value from printing: returned results can be reused and tested by other code.

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Key idea

Control flow determines which statements execute. A method packages behavior under a name and can accept parameters and return a value.

Worked example

A method `isWeekend(day)` returns whether a day code belongs to the weekend; a caller decides what message to show.

Try it

Design a method that finds the largest of three integers. Include how ties are handled.

Suggested check

Accept three `int` parameters, compare them with `Math.max` or explicit branches, and return the largest value. Equal inputs naturally produce the same maximum.

MODULE 03Ready to learn

Classes, objects, and encapsulation

Use constructors to create valid objects. Make fields private and provide methods that enforce rules rather than allowing arbitrary state changes. Separate class responsibilities so each type has a clear purpose.

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Key idea

A class defines fields and methods; an object is an instance of that class. Encapsulation keeps state private and exposes controlled operations.

Worked example

A `TemperatureReading` object stores a value and unit and converts through a method that checks the unit before calculation.

Try it

Model a library book with a private checkout flag and methods for borrowing and returning it.

Suggested check

A `Book` class can keep `checkedOut` private. `borrow()` should fail or return false if it is already checked out; `returnBook()` restores availability.

MODULE 04Ready to learn

Inheritance and interfaces

Use inheritance when a true “is-a” relationship shares stable behavior. Favor interfaces for capabilities and use composition when behavior can be assembled from separate parts. Override methods deliberately and use `@Override` to catch signature mistakes.

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Key idea

Inheritance creates a specialized class from a base class. An interface specifies behavior that multiple unrelated classes can promise to implement.

Worked example

A payment flow can accept a `Payable` interface implemented by card and invoice payment classes.

Try it

Choose whether `Square` should extend `Rectangle` or implement a `Drawable` interface, and justify the choice.

Suggested check

A `Drawable` interface is useful when shapes share the ability to draw, regardless of their place in the class hierarchy. Use inheritance only if the subtype preserves the base type's behavioral expectations.

MODULE 05Ready to learn

Exceptions and safe failure

Catch exceptions where the program can recover or add useful context. Do not catch broadly and silently. Use `try-with-resources` for objects such as files that must be closed, even when an error occurs.

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Key idea

An exception signals that normal control flow cannot complete an operation as expected. Checked exceptions must be declared or handled by the caller.

Worked example

A configuration reader reports a missing file clearly while still ensuring the file handle closes after a successful read.

Try it

Plan how a numeric input routine should handle malformed text and an out-of-range value.

Suggested check

Catch parsing failure to ask for valid input; validate the range separately and explain that rule. Avoid treating both cases as the same opaque error.

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