# Changelog {% hint style="warning" %} **This is the manual for older MicroStream versions (Version < 5.0).** **The new documentation (Version >= 5.0) is located at:** [https://docs.microstream.one/](https://docs.microstream.one/manual) {% endhint %} ## 4.1 ### **Features** * API to create [full backup](https://manual.docs.microstream.one/data-store/configuration/backup/full-backup) additional to [continuous backup](https://manual.docs.microstream.one/data-store/configuration/backup/continuous-backup) * Simplified usage of other NIO based file systems, e.g. in-memory file systems for unit testing * OSGi Headers are added in released jar files and a p2 update site is available next to the maven repository * Additional [storage targets](https://manual.docs.microstream.one/data-store/storage-targets) * AWS S3 and DynamoDB * Azure Storage * Hazelcast * Kafka * MongoDB * Redis * Plain JDBC: SAP HANA, PostgreSQL, MariaDB ### **Bugfixes** * Fixed type handler incompatibilities with JDK 11 * Removed wrongfully initial values in configuration for deletion and truncation directories ### **Migration guide** From 4.1 no actions are necessary, for older versions see below. ## 4.0 ### **Features** * File System Abstraction to support a variety of [storage targets](https://manual.docs.microstream.one/data-store/storage-targets). * Exporter API for storage configuration. ### **Bugfixes** * Better error handling in housekeeping, to avoid storage channel thread interruptions. * Fixed XML loading bug under Android. ### **Migration guide** All configuration code, which includes file paths, may be rewritten to use the new Abstract File System.\ For example see [Storage Files](https://manual.docs.microstream.one/data-store/configuration/storage-files-and-directories) or [Backup](https://manual.docs.microstream.one/data-store/configuration/backup). ## 3.0.1 Bugfix release for projects using an old non public version. ### **Bugfixes** * Fixed bug in type dictionary parser for old legacy type handlers ## 3.0 ### **Features** * Added a convenience layer for defining [custom type handlers](https://manual.docs.microstream.one/data-store/customizing/custom-type-handler) * Fully automatic [lazy reference managing](https://manual.docs.microstream.one/data-store/loading-data/lazy-loading/clearing-lazy-references#automatically) for clearing older `Lazy` references as free memory gets lower. * Completed optimized persistence handling for [remaining types in JDK](https://manual.docs.microstream.one/data-store/addendum/specialized-type-handlers) that are reasonable to appear in entity graphs. E.g. `Currency`, `Locale`, `URI`, `URL`, `Path` * Compatibility with projects using java modules ("jigsaw") * Added JavaDoc for common types like `StorageConnection`, `StorageManager`, `StorageController`, etc. * Auto-recognition for CSV separator character in configuration files (e.g. legacy type mapping) * JSR-107 compatible [JCache provider](https://manual.docs.microstream.one/cache/overview) with additional [Hibernate cache region factory](https://manual.docs.microstream.one/cache/use-cases/hibernate-second-level-cache) * [Storage REST Service and Client](https://manual.docs.microstream.one/data-store/rest-interface) are available to access the storage data via REST, a Java-Wrapper thereof and a Web-UI ### **Bugfixes** * Fixed a potential race condition during loading * Fixed a potential race condition and robustness issue during storing * `StorageConnectionFoundation` instance is now properly created on demand. * Removed unnecessary memory consumption exponential to channel count. * Improved exception messages on invalid configuration values (file sizes etc.) * Workarounded a JDK bug regarding file locking when importing files (JDK exception says another process is locking the file which is outright wrong) * Fixed type resolving problems when different ClassLoaders are involved. * Fixed a bug that caused loading of zero-length arrays to throw an exception despite everything being fine. * Various smaller bugfixes for unnecessary exceptions in special cases and state robustness after exceptions. ### **Migration guide** From 2.2 no actions are necessary, for older versions see below. ## 2.2 ### Features * Removed `SelfStoring` without replacement since it could not be used recursively and has no advantages over just creating a static storing utility method for a certain entity. * Added state validation of value type objects (e.g. String, Integer, BigDecimal, etc.) upon loading. This is hardly relevant in practice, but not having it can lead to confusing hello-world-like test applications. * `EmbeddedStorageManager` now implements `java.lang.AutoClosable`. * Replaced all provisional `RuntimeException`s with either `PersistenceException` or `StorageException`, depending on the architectural level the corresponding source code it located. * The two technically different root handling concepts ("default" and "custom") have been consolidated in a way that they are the same thing on the API level and interchangeable, meaning no more confusion with those root exception messages. * All entity fields of type `transient EmbeddedStorageManager` now get a reference to the used `EmbeddedStorageManager` instance set upon loading/updating. * The interfaces around storage managing have been enhanced so that it is now equally valid to just write `StorageManager` instead of `EmbeddedStorageManager`. (An `EmbeddedStorageManager` "is a" `StorageManager`) * Slight technical consolidation of Lazy reference handling caused the type Lazy to be moved from the package `one.microstream.persistence.lazy` to `one.microstream.reference`. The reason is that the lazy handling has actually no inherent connection to persistence or storage. It's actually just a generic concept that can be used by those layers. See [Migration Guide](#migration-guide) below on how to adjust existing projects. ### Bugfixes * Fixed an off-heap memory leak when restarting the storage multiple times in the same process. * Fixed a bug where changing the fields of an entity type caused an exception. This was a regression bug from fixing a similar problem for another case in version 2.1. Now, both cases work correctly. ### Migration Guide All occurrences in user code of `one.microstream.persistence.lazy.Lazy` have to be refactored to `one.microstream.reference.Lazy`. Modern IDEs provide a functionality to "auto-import" missing types or automatically "organize imports", so this should be resolved with a proverbial push of a button. ## 2.1 ### Features * Android support\ MicroStream is now Java-wise fully compatible with Android. * Replaced all usages of `java.util.File` with `java.nio.file.Path` to allow using custom file implementations. * Improved skipping functionality of Storers (see `EmbeddedStorageManager#createStorer` and `Storer#skip`). * The class Lazy is now an interface to allow custom implementations. See Migration guide below. ### Bugfixes * Fixed a few minor bugs in the skipping functionality of Storers. * Fixed a bug where files remained locked after the storage was shut down. * Fixed a bug where files remained locked after an exception in storage initialization. * Enums defining an abstract method are now handled correctly. * By default, all threads created by MicroStream now start with the prefix "MicroStream-". This can be customized by the new interface `StorageThreadNameProvider`. * Fixed a NullPointerException in import. * Fixed a bug that caused enums with a certain field layout to be loaded inconsistently. * `java.util.Locale` is now persisted and created using Locale's `#toLanguageTag` and `#forLanguageTag`. ### Migration Guide In the directory of an existing storage, in the TypeDictionary file (default name "PersistenceTypeDictionary.ptd"), all occurances of "one.microstream.persistence.lazy.Lazy" must be replaced with "one.microstream.persistence.lazy.Lazy$Default".