Learn Processing-java - 10 Code Examples & CST Typing Practice Test

Processing (Java mode) is a flexible software sketchbook and language for learning how to code within the context of visual arts. It is built on Java and provides a simplified syntax to create graphics, animations, and interactive applications.

View all 10 Processing-java code examples →

Hello World in Processing (Java)Moving Circle Bouncing Ball Colorful Rectangles Mouse Follow Circle Random Stars Growing Circle Rotating Line Random Walk Interactive Rectangle

Learn PROCESSING-JAVA with Real Code Examples

Updated Nov 26, 2025

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Code Sample Descriptions

Hello World in Processing (Java)

void setup() {
    size(400, 200);
    background(255);
    fill(0);
    textSize(32);
    text("Hello World", 100, 100);
}

A simple Processing sketch that displays 'Hello World' in a window.

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Moving Circle

float x = 0;
void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    ellipse(x, 100, 50, 50);
    x += 2;
    if(x > width) x = 0;
}

A circle moving horizontally across the canvas.

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Bouncing Ball

float x = 200, y = 100;
float xspeed = 3, yspeed = 2;
void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    x += xspeed;
    y += yspeed;
    if(x > width || x < 0) xspeed *= -1;
    if(y > height || y < 0) yspeed *= -1;
    ellipse(x, y, 50, 50);
}

A ball bouncing off the edges of the canvas.

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Colorful Rectangles

void setup() {
    size(400, 200);
    noLoop();
}
void draw() {
    for(int i=0; i<10; i++) {
        fill(random(255), random(255), random(255));
        rect(i*40, 50, 30, 100);
    }
}

Draws a series of colored rectangles.

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Mouse Follow Circle

void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    fill(0, 100, 255);
    ellipse(mouseX, mouseY, 50, 50);
}

A circle that follows the mouse cursor.

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Random Stars

void setup() {
    size(400, 200);
    background(0);
}
void draw() {
    fill(255);
    eclipse(random(width), random(height), 2, 2);
}

Draws random stars on the canvas every frame.

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Growing Circle

float r = 10;
void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    ellipse(width/2, height/2, r, r);
    r += 1;
    if(r > width) r = 10;
}

A circle that grows in size over time.

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Rotating Line

float angle = 0;
void setup() {
    size(400, 200);
    background(255);
}
void draw() {
    background(255);
    translate(width/2, height/2);
    line(0, 0, 100*cos(angle), 100*sin(angle));
    angle += 0.05;
}

A line rotating around the center of the canvas.

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Random Walk

float x, y;
void setup() {
    size(400, 200);
    x = width/2;
    y = height/2;
    background(255);
}
void draw() {
    stroke(0);
    x += random(-5, 5);
    y += random(-5, 5);
    point(x, y);
}

A point performing a random walk across the canvas.

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Interactive Rectangle

void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    if(mousePressed) {
        rect(150, 50, 100, 100);
    } else {
        rect(150, 50, 50, 50);
    }
}

Rectangle width changes when mouse is pressed.

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Frequently Asked Questions about Processing-java

What is Processing-java?

What are the primary use cases for Processing-java?

Creating 2D and 3D interactive graphics. Prototyping generative art or animation projects. Teaching programming concepts with visual feedback. Building interactive installations and exhibits. Rapidly testing visual or computational ideas before scaling

What are the strengths of Processing-java?

Rapid prototyping for visual projects. Great learning tool for beginners and designers. Wide library ecosystem for multimedia. Cross-platform and open-source. Large collection of example sketches and community support

What are the limitations of Processing-java?

Performance limited for very complex or high-resolution projects. Java mode adds JVM overhead, slower than optimized Java applications. 3D support basic compared to specialized 3D engines. Not ideal for production-level software outside art/design context. Some advanced Java features require workarounds or full Java knowledge

How can I practice Processing-java typing speed?

CodeSpeedTest offers 10+ real Processing-java code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Learn Processing-java - 10 Code Examples & CST Typing Practice Test

Code Sample Descriptions

Hello World in Processing (Java)

void setup() {
    size(400, 200);
    background(255);
    fill(0);
    textSize(32);
    text("Hello World", 100, 100);
}

A simple Processing sketch that displays 'Hello World' in a window.

Let’s Try →

Moving Circle

float x = 0;
void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    ellipse(x, 100, 50, 50);
    x += 2;
    if(x > width) x = 0;
}

A circle moving horizontally across the canvas.

Let’s Try →

Bouncing Ball

float x = 200, y = 100;
float xspeed = 3, yspeed = 2;
void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    x += xspeed;
    y += yspeed;
    if(x > width || x < 0) xspeed *= -1;
    if(y > height || y < 0) yspeed *= -1;
    ellipse(x, y, 50, 50);
}

A ball bouncing off the edges of the canvas.

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Colorful Rectangles

void setup() {
    size(400, 200);
    noLoop();
}
void draw() {
    for(int i=0; i<10; i++) {
        fill(random(255), random(255), random(255));
        rect(i*40, 50, 30, 100);
    }
}

Draws a series of colored rectangles.

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Mouse Follow Circle

void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    fill(0, 100, 255);
    ellipse(mouseX, mouseY, 50, 50);
}

A circle that follows the mouse cursor.

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Random Stars

void setup() {
    size(400, 200);
    background(0);
}
void draw() {
    fill(255);
    eclipse(random(width), random(height), 2, 2);
}

Draws random stars on the canvas every frame.

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Growing Circle

float r = 10;
void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    ellipse(width/2, height/2, r, r);
    r += 1;
    if(r > width) r = 10;
}

A circle that grows in size over time.

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Rotating Line

float angle = 0;
void setup() {
    size(400, 200);
    background(255);
}
void draw() {
    background(255);
    translate(width/2, height/2);
    line(0, 0, 100*cos(angle), 100*sin(angle));
    angle += 0.05;
}

A line rotating around the center of the canvas.

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Random Walk

float x, y;
void setup() {
    size(400, 200);
    x = width/2;
    y = height/2;
    background(255);
}
void draw() {
    stroke(0);
    x += random(-5, 5);
    y += random(-5, 5);
    point(x, y);
}

A point performing a random walk across the canvas.

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Interactive Rectangle

void setup() {
    size(400, 200);
}
void draw() {
    background(255);
    if(mousePressed) {
        rect(150, 50, 100, 100);
    } else {
        rect(150, 50, 50, 50);
    }
}

Rectangle width changes when mouse is pressed.

Let’s Try →

Frequently Asked Questions about Processing-java

What is Processing-java?

What are the primary use cases for Processing-java?

What are the strengths of Processing-java?

What are the limitations of Processing-java?

How can I practice Processing-java typing speed?

CodeSpeedTest offers 10+ real Processing-java code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.