Java 8 is outdated ;)

why_its_better.java

// alt
void onCommand(CommandSender sender) {
  if (sender instanceof Player) {
    Player player = (Player) sender;
  }
}

// neu
void onCommand(CommandSender sender) {
  if (sender instanceof Player player) {
    player.doSomething(); // player wird zu PLayer gecasted
  }
}

// Alt
String input = "test";
String result;
switch (input) {
  case "te":
  case "est":
    result = "te est";
    break;
  case "tEsT":
    result = "TeSt";
    break;
  case "test":
    result = "test";
    break;
}

// neu
String input = "test";
String result = switch (input) {
  case "te", case "est" -> "te est";
  case "tEsT" -> "TeSt";
  case "test" -> "test";
}

// Alt
BufferedReader reader = new BufferedReader();
// neu
var reader = new BufferedReader();

// Alt
List<String> list = new ArrayList<>();
list.add("a");
list.add("a");
list.add("a");
list.add("a");
// Neu
List<String> list = List.of("a", "a", "a", "a");

// Alt
String sql = "SELECT * FROM table \n" +
              WHERE x = y";
// Neu
String sql = """SELECT * FROM table
              WHERE x = y";"""
//Alt
ObjectThatHasFieldCalledI a;
a.i = "test; // => npe weil a ist null
java.lang.NullPointerException: null
  <stacktrace>
//neu
ObjectThatHasFieldCalledI a;
a.i = "test; // => npe weil a ist null
java.lang.NullPointerException: Cannot assign field "i" because "a" is null
  <stacktrace>