# owner | Matteo Baccan | Knowledge Base | Instagit

Get rid of the boilerplate code in properties based configuration.

GitHub Stars: 938

Repository: https://github.com/matteobaccan/owner

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## Articles

### [How to Handle Null Values and Specify Separators for Collection Properties in OWNER](/matteobaccan/owner/how-to-handle-null-values-and-specify-separators-for-collection-properties)

Learn how to handle null values and specify separators for OWNER collection properties. Customize default behaviors with annotations like @DefaultValue and @Separator.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Configure Property Load Order with LoadType.FIRST vs LoadType.MERGE in OWNER](/matteobaccan/owner/how-to-configure-load-order-with-loadtype-first-vs-loadtype-merge)

Learn how to configure property load order in OWNER using LoadType FIRST vs MERGE. Control property source precedence and handle duplicate keys effectively.

- Tags: deep-dive
- Published: 2026-03-07

### [How to Load and Merge XML Property Files Using XMLLoader in Owner](/matteobaccan/owner/how-to-load-and-merge-xml-property-files-using-xmlloader)

Effortlessly load and merge XML property files with Owner XMLLoader. Parse standard Java XML or custom hierarchies and combine multiple files using @LoadType MERGE. Get started now.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Implement the Reloadable Interface for Manual Property Reload in Owner](/matteobaccan/owner/how-to-implement-reloadable-interface-for-manual-property-reload)

Implement the Reloadable interface in OWNER for manual property reloads. Extend Reloadable with Config and call reload() to refresh properties at runtime without app restarts.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Use the Owner ConfigFactory API to Create and Manage Configuration Instances](/matteobaccan/owner/how-to-use-configfactory-api-to-create-and-manage-configuration-instances)

Discover how to use the Owner ConfigFactory API to create and manage type-safe configuration instances. Leverage property loading, variable expansion, and hot-reload features for robust configuration management.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Handle Parameter Formatting with Placeholders in Owner Configuration](/matteobaccan/owner/how-to-handle-parameter-formatting-with-0-1-placeholders-in-values)

Learn how to handle parameter formatting in Owner configuration using String.format with percent-style placeholders for dynamic values. Get clear syntax examples.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Convert Properties to Collections (List, Set, and Map) in Owner](/matteobaccan/owner/how-to-convert-properties-to-collections-like-list-set-and-map-types)

Learn how to convert properties to collections List Set and Map in Owner. Discover Owner's automatic type conversion for Lists and Sets and how to implement custom Converters for Maps.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Implement a Custom ZooKeeper Loader from the Owner-Extras Module](/matteobaccan/owner/how-to-implement-custom-zookeeper-loader-from-owner-extras-module)

Learn to implement a custom ZooKeeper loader in OWNER. Handle zookeeper URIs, extract properties using Apache Curator, and register your loader for flexible configuration management.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Use Variable Expansion in @Sources Annotations with Imports](/matteobaccan/owner/how-to-use-variable-expansion-in-sources-annotations-with-imports)

Learn variable expansion in @Sources annotations with imports in Owner. Understand runtime variable resolution using environment variables system properties and import maps.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Implement Transactional Property Changes with Rollback Capability in Owner](/matteobaccan/owner/how-to-implement-transactional-property-changes-with-rollback-capability)

Implement transactional property changes in Owner with rollback. Intercept and abort changes or batches using rollback exceptions for robust configuration management.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Use JMX Support for Runtime Configuration Management in Owner](/matteobaccan/owner/how-to-use-jmx-support-for-runtime-configuration-management)

Master JMX support in Owner for runtime configuration management. Effortlessly read and update properties via JConsole without application restarts.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Load Properties from Classpath, File System, and Custom URIs in OWNER](/matteobaccan/owner/how-to-load-properties-from-classpath-file-system-and-custom-uris)

Load OWNER properties from classpath file system and custom URIs using @Config.Sources. Implement Loader interface for proprietary schemes.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Listen to Reload Events Using the ReloadListener Interface in Owner](/matteobaccan/owner/how-to-listen-to-reload-events-using-reloadlistener-interface)

Learn to listen for reload events in Owner using the ReloadListener interface. Implement and register the listener to get callbacks after configuration reloads.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Implement a Preprocessor to Transform Property Values Before Use in Owner](/matteobaccan/owner/how-to-implement-preprocessor-to-transform-property-values-before-use)

Learn how to implement a Preprocessor in OWNER to transform property values before type conversion. Intercept and modify raw strings for custom value manipulation.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Disable Variable Expansion or Parameter Formatting with @DisableFeature in Owner](/matteobaccan/owner/how-to-disable-variable-expansion-or-parameter-formatting-with-disablefeature)

Disable variable expansion and parameter formatting in Owner using @DisableFeature. Control config processing at method or class level for precise configuration management with the Owner library.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Set Default Values with @DefaultValue When Properties Are Missing in Owner](/matteobaccan/owner/how-to-set-default-values-with-defaultvalue-when-properties-are-missing)

Learn how to set default values with @DefaultValue in Owner. Automatically provide fallback strings for missing properties, ensuring type conversion and robust configuration.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Use the @Key Annotation to Map Method Names to Custom Property Keys in Owner](/matteobaccan/owner/how-to-use-key-annotation-to-map-method-names-to-custom-property-keys)

Learn how to use the @Key annotation in Owner to map interface methods directly to custom property keys overriding default behavior. Simplify your configuration mapping.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Register Custom Loader Implementations for Additional File Formats in Owner](/matteobaccan/owner/how-to-register-custom-loader-implementations-for-additional-file-formats)

Learn to register custom Loader implementations for new file formats in Owner Repository. Implement the Loader interface and call registerLoader before creating configurations.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Use a Custom Tokenizer to Split Comma-Separated Property Values in Owner](/matteobaccan/owner/how-to-use-custom-tokenizer-to-split-comma-separated-property-values)

Learn how to use a custom tokenizer in OWNER to split comma separated property values. Override the default tokenizer with the TokenizerClass annotation for flexible parsing.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Create Custom Converter Implementations for Property Types in Owner](/matteobaccan/owner/how-to-create-custom-converter-implementations-for-property-types)

Implement the org.aeonbits.owner.Converter interface to create custom converter implementations for property types in the Owner library. Learn how to bind your deserialization logic.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Use Variable Expansion with ${variable} Syntax in OWNER Property Values](/matteobaccan/owner/how-to-use-variable-expansion-with-variable-syntax-in-property-values)

Learn to use variable expansion with ${variable} syntax in OWNER property values. Dynamically configure settings using environment variables system properties and custom maps in property files and Java annotations.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Encrypt and Decrypt Property Values Using the @EncryptedValue Annotation in Owner](/matteobaccan/owner/how-to-encrypt-and-decrypt-property-values-using-encryptedvalue-annotation)

Secure sensitive property values in Owner with the @EncryptedValue annotation. Learn to implement Decryptor for transparent runtime decryption and protect your configuration.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Load Multiple Property Files with the MERGE Load Policy in Owner](/matteobaccan/owner/how-to-load-multiple-property-files-with-merge-load-policy)

Learn to load multiple property files with the MERGE load policy in Owner. Aggregate sources with LoadType.MERGE for unified configurations where earlier files take precedence. Optimize your Java config.

- Tags: how-to-guide
- Published: 2026-03-07

### [How to Implement Hot Reload with Async and Sync Modes in OWNER API](/matteobaccan/owner/how-to-implement-hot-reload-with-async-and-sync-modes-in-owner-api)

Implement hot reload in OWNER API with SYNC or ASYNC modes for dynamic configuration updates. Easily monitor changes on method invocation or background threads. Boost your development.

- Tags: how-to-guide
- Published: 2026-03-07