Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

// Java 16+ record
record Point(double x, double y) {
    // Compact canonical constructor with validation
    Point {
        if (Double.isNaN(x) || Double.isNaN(y))
            throw new IllegalArgumentException("NaN coordinates not allowed");
    }

// Additional methods are allowed
    double distanceTo(Point other) {
        double dx = this.x - other.x;
        double dy = this.y - other.y;
        return Math.sqrt(dx * dx + dy * dy);
    }
}

// Builder pattern
class HttpRequest {
    private final String url;
    private final String method;
    private final int    timeoutMs;
    private final java.util.Map<String, String> headers;

private HttpRequest(Builder b) {
        this.url       = b.url;
        this.method    = b.method;
        this.timeoutMs = b.timeoutMs;
        this.headers   = java.util.Collections.unmodifiableMap(b.headers);
    }

@Override public String toString() {
        return method + " " + url + " (timeout=" + timeoutMs + "ms, headers=" + headers + ")";
    }

static class Builder {
        private final String url;
        private String method  = "GET";
        private int    timeoutMs = 5_000;
        private final java.util.Map<String, String> headers = new java.util.LinkedHashMap<>();

Builder(String url) { this.url = url; }
        Builder method(String m)          { this.method = m; return this; }
        Builder timeout(int ms)           { this.timeoutMs = ms; return this; }
        Builder header(String k, String v){ this.headers.put(k, v); return this; }
        HttpRequest build()               { return new HttpRequest(this); }
    }
}

public class ClassDesignPatterns {
    public static void main(String[] args) {
        // Record usage
        Point a = new Point(0, 0);
        Point b = new Point(3, 4);
        System.out.println("Distance: " + a.distanceTo(b)); // 5.0
        System.out.println(b);                               // Point[x=3.0, y=4.0]

// Builder pattern
        HttpRequest req = new HttpRequest.Builder("https://api.example.com/data")
            .method("POST")
            .timeout(10_000)
            .header("Content-Type", "application/json")
            .header("Authorization", "Bearer token123")
            .build();
        System.out.println(req);
    }
}