Java supports sealed classes (which is close enough to sum types at least for the stuff I work on), and pattern matching over them is in preview. https://openj

Java supports sealed classes (which is close enough to sum types at least for the stuff I work on), and pattern matching over them is in preview. https://openjdk.org/jeps/409 https://openjdk.org/jeps/409 https://openjdk.org/jeps/427 https://openjdk.org/jeps/427