Java

To use varlock with Java, install the standalone binary and run your app under varlock run. It loads and validates your env, then injects it into the process.

Add @generateJavaEnv to your schema to generate a small, self-contained class: a typed Env with public final fields, a static load() that parses the injected __VARLOCK_ENV blob, and a SENSITIVE_KEYS constant.

# @generateJavaEnv(path=src/main/java/Env.java)

The file is regenerated automatically on varlock load and varlock run, or explicitly with varlock codegen. Requires Java 17+ and Jackson on the classpath (jackson-databind):

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-databind</artifactId>
  <version>2.17.2</version>
</dependency>

Optional package= and class= set the Java package and class name (default: no package, class Env). Field names are camelCase (DB_HOST → dbHost).

Reading values

Call load() once, then read fields off the object. Required scalars are primitives (long, boolean, …); optional ones are boxed (Long, Boolean, …) and may be null:

Env e = Env.load();          // call once, hold or pass `e` around
String host = e.dbHost;      // String (required field)
if (e.dbPort != null) {      // Long (optional field)
    System.out.println(host + ":" + e.dbPort);
}

Build a jar as usual, then run it under varlock:

mvn -q package
varlock run -- java -jar target/myapp.jar

With Spring Boot, wrap the usual run goal (or the packaged jar) the same way:

varlock run -- ./mvnw spring-boot:run
# or, after `./mvnw -q package`:
varlock run -- java -jar target/myapp.jar

load() throws a clear error if __VARLOCK_ENV is missing (e.g. you forgot varlock run) or if a required key is absent.

Every load() call re-parses the blob. To avoid reloading, bind the loaded instance wherever your app keeps shared config.

Spring: expose it as a @Bean and inject Env where you need it:

@Configuration
public class EnvConfig {
  @Bean
  public Env env() {
    return Env.load(); // call once at startup
  }
}

@Service
public class DbService {
  private final Env env;

  public DbService(Env env) {
    this.env = env;
  }

  public void connect() {
    // env.dbHost, env.dbPort, …
  }
}

No DI container? A small holder works:

public final class Config {
  public static final Env ENV = Env.load();
}

// elsewhere: Config.ENV.dbPort  (Long)

Java

Reading values

Sharing one instance