Objects.requireNonNullElse()

// Old NPE message:
// "NullPointerException"
// at MyApp.main(MyApp.java:42)
// Which variable was null?!

// Verbose error class
public class ErrorResponse {
    private final int code;
    private final String message;
    // constructor, getters, equals,
    // hashCode, toString...
}

String city = null;
if (user != null) {
    Address addr = user.getAddress();
    if (addr != null) {
        city = addr.getCity();
    }
}
if (city == null) city = "Unknown";