<dependency> <groupId>org.contract4j5</groupId> <artifactId>contract4j5-annotations</artifactId> <version>2.6.1</version> </dependency> public class Calculator { public int divide(int x, int y) { // Preconditions if (y == 0) { throw new IllegalArgumentException("Cannot divide by zero!"); } // Postconditions if ((x / y) * y != x) { throw new RuntimeException("Incorrect division result!"); } return x / y; } }