🧛 Dracula Theme Preview - Code Syntax Highlighting

Java 21 Example

Java - Record with Validation
public record Transaction(
    long id,
    String category,
    double amount,
    String description,
    LocalDate date
) {
    public Transaction {
        if (id <= 0) throw new IllegalArgumentException(
            "ID must be positive");
        Objects.requireNonNull(category);
        if (amount <= 0) throw new IllegalArgumentException(
            "Amount must be positive");
    }
}

Stream Processing Examples

Java 21
// Filter and collect
List<Transaction> filtered =
    transactions.stream()
        .filter(t -> t.amount() >= 50.0)
        .toList();

// Group by category
Map<String, Double> totals =
    transactions.stream()
        .collect(Collectors.groupingBy(
            Transaction::category,
            Collectors.summingDouble(
                Transaction::amount
            )
        ));
Scala 3
// Filter directly
val filtered = transactions
  .filter(_.amount >= 50.0)

// Group and sum in one pass
val totals = transactions
  .groupMapReduce(_.category)(_.amount)(_ + _)
Kotlin
// Filter directly
val filtered = transactions
    .filter { it.amount >= 50.0 }

// Group and calculate totals
val totals = transactions
    .groupBy { it.category }
    .mapValues { (_, txns) ->
        txns.sumOf { it.amount }
    }

String Manipulation

Java 21 - Text Blocks
String json = """
    {
        "name": "%s",
        "email": "%s",
        "active": %b
    }
    """;

System.out.println(json.formatted("Alice", "alice@example.com", true));

Inline Code Examples

Use List.of() to create immutable lists in Java 9+. Similarly, Set.of() and Map.of() provide immutable collections.

In Scala, collections are immutable by default: List("a", "b", "c")

Kotlin uses listOf() for read-only lists and mutableListOf() for mutable ones.

Color Reference

Element Color Dracula Name
Keywords (public, class, if) â–  Pink #ff79c6
Strings â–  Yellow #f1fa8c
Functions â–  Green #50fa7b
Classes/Types â–  Cyan #8be9fd
Numbers â–  Purple #bd93f9
Comments â–  Blue-Gray #6272a4