What if Spring Boot had Kotlin-style null-safety without migrating to Kotlin?

#java #opensource #showdev #tooling

I've been working on JADEx (Java Advanced Development Extension) which is a safety layer that makes Java safer by adding Null-Safety and Final-by-Default semantics without rewriting Java codes and modifying the JVM.

Quick recap of what JADEx adds to Java:

String? nullable type declaration
?. null-safe access operator
?: Elvis operator
apply readonly final-by-default mode per file

Today I'm sharing three things that just landed.

1. Lombok support

This was the most requested thing. JADEx now integrates with Lombok via a Delombok pipeline internally. The key motivation: JADEx's nullability checker needs to see Lombok-generated code (getters, builders, constructors) to avoid blind spots. Without Delombok, nullable fields could silently pass through generated methods unchecked.

@Data
@Builder
@Entity
public class User {
    private String name;
    private String? email;      // @Nullable propagated to getter + builder param
    private Address? address;   // @Nullable propagated to getter + builder param
}

After Delombok, JADEx sees and analyzes the generated code:

// Lombok-generated — JADEx propagates @Nullable into these
@Nullable
public String getEmail() { return this.email; }

public UserBuilder email(@Nullable final String email) { ... }
public UserBuilder address(@Nullable final Address address) { ... }

2. Gradle plugin published

The JADEx Gradle plugin is now on Maven Central and the Gradle Plugin Portal.

plugins {
    id 'io.github.nieuwmijnleven.jadex' version '0.628'
}

jadex {
    sourceDir = 'src/main/jadex'
}

That's the only change needed to an existing Spring Boot project. Everything else (compilation, Delombok pipeline, .java generation) is handled automatically.

3. JADEx Spring Boot example project