How do you create a smooth game loop with separate UPS and FPS in a Java Swing 2D platformer?

Use delta accumulators: update game logic at a fixed UPS and render independently at a target FPS. This keeps movement and physics consistent even when rendering speed varies.

How can a Java 2D platformer load and draw a sprite atlas from the classpath?

Load the image with getResourceAsStream, create a BufferedImage, then use getSubimage to select a sprite. Draw it with Graphics.drawImage using scaled destination dimensions.

How is horizontal camera scrolling implemented in a Java platformer?

Track an x-level offset and subtract it from world objects when drawing. Update the offset when the player passes a screen threshold, while clamping it to level bounds.

Free Course Image How to make a game Platformer 2D in Java

Free online course How to make a game Platformer 2D in Java

Duration of the online course: 17 hours and 52 minutes

New

Build your own 2D platformer in Java with this free online course—game loop, collisions, animations, enemies and menus, plus a certificate-ready project.

In this free course, learn about

Set up a Swing window & GamePanel correctly (setVisible timing) to avoid blank rendering
Capture keyboard input reliably: KeyListener setup, focus handling, and resetting input on focus loss
Implement a controllable game loop with fixed UPS/FPS, delta accumulators, and consistent timing
Load sprite atlases from the classpath and render scaled subimages in Java2D
Build animation systems: frame indexing, animation speed control, and per-entity animations
Design Player architecture: movement states, hitboxes, and clean separation of update/render logic
Create levels from tilemaps/images: tile type mapping, efficient parsing, and player spawn points
Handle collisions & physics: pre-move overlap prevention, gravity/air acceleration, and ground checks
Implement GameStates with enums/interfaces for menu, pause, gameplay, and overlays
Create UI components: menu buttons, URM buttons, audio/music/SFX toggles, and options sharing
Add scrolling camera & parallax backgrounds (cloud layers) for larger levels
Build enemy systems: enemy manager, patrol edge checks, aggro/attack triggers, and health bars
Implement objects/traps/cannons/projectiles with correct hitboxes, sequences, and tile collisions
Handle death/restart flows and bug fixes; add character selection via maintainable animation metadata

About the free online course

Create a complete 2D platformer from scratch while strengthening your Java fundamentals and building practical game development skills. This free online course guides you through the real decisions behind a playable game: how to open a reliable Swing window, capture responsive input, and draw smooth graphics without flicker. You will move beyond isolated snippets and learn how systems fit together to form a game that feels tight, readable, and expandable.

Step by step, you will shape a solid foundation around timing and performance. You will implement a controllable game loop, understand why separating updates from rendering matters, and keep motion consistent across different machines. From there, you will bring the world to life with sprite atlases, animation control, and a player that moves convincingly with gravity, jumping, and robust collision rules that prevent clipping through tiles.

As the project grows, you will learn how to organize code so it stays maintainable: using game states to switch cleanly between gameplay, menus, pause overlays, options, and game over screens. You will also tackle essential game feel features such as scrolling levels, parallax backgrounds, UI buttons with proper visual states, and audio that behaves predictably across screens.

The course rounds out the experience by adding enemies with patrol and attack behavior, interactive objects, traps, cannons, projectiles, health bars, multiple levels, and tools to build your own stages from images. Along the way, you will practice debugging and polishing edge cases such as focus loss, state resets after restart, and consistent collision checks. By the end, you will have a working platformer framework you can extend with new characters, levels, and mechanics—ideal for a portfolio piece or a starting point for your next game.

Course content

Video class: A New Beginning - Episode #01 - Java Game Development Tutorial 27m
Exercise: When setting up the Swing window for a Java 2D platformer, where should you call setVisible(true) to avoid a blank screen?
Video class: INPUTS - Episode #02 - Platformer Game Tutorial Java 20m
Exercise: Which step ensures your GamePanel receives keyboard events after adding a KeyListener?
Video class: GAME LOOP - Episode #03 - Platformer Tutorial Java 28m
Exercise: Which game loop approach gives consistent, controllable FPS in a Java Swing 2D platformer?
Video class: HOW TO MAKE A Game Loop in Java - Platformer GameDev 2022 00m
Exercise: What kind of game loop should you implement for a 2D Java platformer and why?

Video class: IMAGES - Episode #04 - Platformer Tutorial Java 15m
Exercise: How do you correctly load a sprite atlas from the classpath and render a 64x40 subimage at double size in a Java 2D platformer panel?
Video class: ANIMATIONS - Episode #05 - Platformer Tutorial Java 29m
Exercise: What does the animation speed variable control in the 2D platformer animation loop?
Video class: GAME LOOP 2.0 - Episode #06 - Platformer Tutorial Java 14m
Exercise: Why separate UPS from FPS and use delta accumulators in a 2D platformer game loop?
Video class: PLAYER CLASS - Episode #07 - Platformer Tutorial Java 27m
Exercise: What is the correct way to prevent the player from continuing to move when the game window loses focus?

Video class: Level Creation - Episode #08 - Platformer Tutorial Java 28m
Exercise: How are tile types for a level determined in the implementation?
Video class: Collision Detection - Episode #09 - Platformer Tutorial Java 29m
Exercise: How does the player prevent overlapping tiles before moving?
Video class: GRAVITY - Episode #10 - Platformer Tutorial Java 32m
Exercise: Which variable determines the player's downward acceleration while in the air in a 2D platformer?

Video class: GAMESTATES - Episode #11 - Platformer Tutorial Java 25m
Exercise: What is the main benefit of using an enum based GameState with a StateMethods interface in a Java 2D platformer
Video class: HOW TO CREATE a MENU - Episode #12 - Platformer Tutorial Java 34m
Exercise: Which index mapping is correct for MenuButton image states in the Java 2D platformer menu?
Video class: PAUSE SCREEN - Episode #13 - Platformer Tutorial Java 33m
Exercise: In the pause overlay, what is the intended behavior of the music and SFX buttons?
Video class: PAUSE SCREEN - PART 2 - Episode #13 - Platformer Tutorial Java 41m
Exercise: How should a pause overlay URM button handle visual states and rendering?

Video class: Bigger Levels - Episode #14 - Platformer Tutorial Java 26m
Exercise: Best approach to implement horizontal scrolling in a 2D platformer
Video class: Background That Moves ? - Episode #15 - Platformer Tutorial Java 17m
Exercise: Implementing Parallax Clouds in a 2D Java Platformer
Video class: ENEMIES - Episode #16 - Part 1 - Platformer Tutorial Java 29m
Exercise: Which class should handle loading, updating, and drawing multiple enemies in a 2D Java platformer?
Video class: ENEMIES - Episode #16 - Part 2 - Platformer Tutorial Java 24m
Exercise: Preventing Enemy From Falling Off Platforms During Patrol
Video class: ENEMIES - Episode #16 - part 3 - Platformer Tutorial Java 38m
Exercise: When will a 2D platformer enemy start turning toward the player and prepare to attack?
Video class: ENEMIES - The Finale - Episode #16 - Platformer Tutorial Java 1h10m
Exercise: How do you correctly compute the dynamic health bar width so it scales with current health?

Video class: MULTIPLE LEVELS - Episode #17 - Platformer Tutorial Java 57m
Exercise: How is the player spawn point determined for each level
Video class: CODE CLEANUP - Episode #18 - Platformer Tutorial Java 17m
Exercise: Centralizing shared logic in a Java 2D platformer
Video class: OBJECTS - Episode #19-part 1/2 - Platformer Tutorial Java 32m
Exercise: How are barrel and box animations managed in the game objects system?
Video class: OBJECTS - Episode #19-part 2/2 - Platformer Tutorial Java 33m
Exercise: Why add y draw offset plus 2 to the container hitbox position in a 2D Java platformer

Video class: TRAPS - Episode #20 - Platformer Tutorial Java 23m
Exercise: What hitbox dimensions should a spike trap use to match gameplay collision?
Video class: CANNONS - Episode #21 - Platformer Tutorial Java 32m
Exercise: What is the correct sequence a cannon uses before firing?
Video class: PROJECTILES - Episode #22 - Platformer Tutorial Java 23m
Exercise: Best point to test cannonball collision with tiles in a 2D Java platformer
Video class: DEATH SCREEN - Episode #23 - Platformer Tutorial Java 22m
Exercise: What is the correct flow to handle player death with animation and a game over overlay in a Java 2D platformer

Video class: OPTIONS MENU- Episode #24 - Platformer Tutorial Java 29m
Exercise: Where should AudioOptions be instantiated to share audio controls across Pause and Options screens in a Java 2D platformer
Video class: SOUNDS - Episode #25 - Platformer Tutorial Java 58m
Exercise: How do you ensure a short sound effect replays every time when using Java Clip in a 2D platformer?
Video class: POWER ATTACK! - Episode #26 - Platformer Tutorial Java 20m
Exercise: In a 2D Java platformer, what power cost is required to start the power attack?

Video class: FIXING BUGS - Episode #27 - Platformer Tutorial Java 21m
Exercise: In a 2D Java platformer, the player continues moving upward after restarting if the restart occurs mid jump. What is the correct state reset to prevent this?
Video class: THE FINAL EPISODE - Platformer Tutorial Java 12m
Exercise: Most efficient way to parse a level image into game data in a basic Java 2D platformer
Video class: How To BUILD YOUR OWN LEVEL - Platformer Tutorial EXTRA 21m
Exercise: Which pixel component decides which terrain tile sprite is drawn in the PNG based level system?
Video class: How To Add CHARACTER SELECTION - Platformer Tutorial EXTRA 1h12m
Exercise: What is the most maintainable way to support multiple characters with different animation rows and frame counts in a Java 2D platformer

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Free online courses on 2D Game Development

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Explore free online 2D game development courses with certificates and learn to create engaging games from scratch. Build practical skills in game design, programming, animation, sprites, physics, level creation, and popular engines. Study at your own pace, strengthen your portfolio, and start your journey toward a career in 2D game development.