Java 21

String invoiceTxt =
    "Hi " + name + ",\n"
  + "please send " + (value + tax) + "€ to us or we eat"
  + "your brain.\n\n"
  + "Sincerely\n"
  + "\tThe 🧟s";

String invoiceTxt = new StringBuilder()
  .append("Hi ").append(name).append(",\n")
  .append("please send ").append(value + tax)
    .append("€ to us or we eat you brain.\n\n")
  .append("Sincerely\n")
  .append("\tThe 🧟s")
  .toString();

String invoiceTxt = """
  Hi %s,
  please send %.2f€ to us or we eat you brain.

  Sincerely
    The 🧟s""".formatted(name, value + tax);
// pre Java 15
String.format("..", name, value + tax);

String name = "Merlin";
int value = 34;
double tax = value * 0.1;

String invoiceTxt = STR."""
  Hi \{ name },
  please send \{ value + tax }€ to us or we eat you brain.

  Sincerely
    The 🧟s""";

// String name; int value; double tax;

String invoiceTxt = FMT."""
  Hi %s\{ name },
  please send %.2f\{ value + tax }€ to us or we eat you brain.

  Sincerely
    The 🧟s""";

@FunctionalInterface
public interface Processor<R, E extends Throwable> {

  // transform StringTemplate to Result
  R process(StringTemplate stringTemplate) throws E;

  // Factory Method for Processors
  static <T> Processor<T, RuntimeException>
    of(Function<? super StringTemplate, ? extends T> process){}
}

class Shuffler implements Processor<String, Throwable> {
  @Override
  public String process(StringTemplate st) throws Throwable {
    var values = st.values().reversed().iterator();
    var sb = new StringBuilder();
    st.fragments().reversed()
      .forEach(frag -> sb.append(frag).append(values.next()));
    return sb.toString();
  }
} // new Shuffler().""

var JSON = StringTemplate.Processor
  .of(st -> new JSONObject(st.interpolate()));

// List
list.get(0); list.get(list.size() -1));
// Sorted Set at least
sortedSet.first(); sortedSet.last();
// Deque (double ended queue)
deque.getFirst(); deque.getLast();

// List
for(var it = l.listIterator(l.size()); it.hasPrevious();){ }
// sorted Set
sortedSet.descendingSet().forEach();
// Deque
for(var it = deque.descendingIterator(); it.hasNext();){ }

// List
l.add(0, "Hallo"); l.add("World");
// sorted Set
var tmp = new TreeSet<String>();
tmp.add("Hallo");
tmp.addAll(sortedSet);
tmp.add("World");
sortedSet = tmp;
// Deque
deque.addFirst("Hello"); deque.addLast("World");

interface SequencedCollection<E> extends Collection<E> {
  // new method
  SequencedCollection<E> reversed();
  // methods promoted from Deque
  void addFirst(E); void addLast(E);
  E getFirst(); E getLast();
  E removeFirst(); E removeLast();
}

interface SequencedSet<E>
    extends Set<E>, SequencedCollection<E> {
  SequencedSet<E> reversed();    // covariant override
}

interface SequencedMap<K,V> extends Map<K,V> {
  // new methods
  SequencedMap<K,V> reversed();
  SequencedSet<K> sequencedKeySet();
  SequencedCollection<V> sequencedValues();
  SequencedSet<Entry<K,V>> sequencedEntrySet();
  V putFirst(K, V); V putLast(K, V);
  // methods promoted from NavigableMap
  Entry<K, V> firstEntry(); Entry<K, V> lastEntry();
  Entry<K, V> pollFirstEntry(); Entry<K, V> pollLastEntry();
}

public class Main {
  public static void main(String[] args) {
    System.out.println("Hello 🧟‍-Land");
  }
}

public class Main {
  public static void main(String[] args) {
    System.out.println("Hello 🧟‍-Land");
  }
}

class Main {
  void main() {
    System.out.println("Hello 🧟‍-Land");
  }
}

void main() {
  System.out.println("Hello 🧟-Land");
}

$ java SomeName.java
Hello 🧟-Land

void main() {
    System.out.println("Goodbye Info Days")
}

int value = 34;
double tax = value * 0.1;
List<String> brainCarrier = //..

void main() {
  FMT."""
  Hi %s\{ brainCarrier.reversed().getFirst() },
  please send %.2f\{ value + tax }€ to us or we eat you brain.

  Sincerely
    The 🧟s""";
}