Supported Java Features

This is the manual for older MicroStream versions (Version < 5.0).
The new documentation (Version >= 5.0) is located at:
​https://docs.microstream.one/​
Feature
Supported
Note
Classes
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Classes without default constructor
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Abstract classes / Interfaces
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Perfectly handleable as types, but there can never be instances to be persisted in the first place.
Inner classes
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Anonymous inner classes
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Primitives
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References
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Final fields
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Static fields
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Not supported since they are outside of an entity graph / a database, i.e. potentially shared by multiple graphs.
Constant primitives
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No sense in persisting those. These are just plain trivial values outside of an entity graph / a database.
Constant instances
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Must be registered for loading to update them instead of creating independent new instances.
Primitive arrays
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Object arrays
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Multi dimensional arrays
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Technically the same as object arrays as every array is an object itself.
JDK value types
(String, Number types, Date, File, Locale, Optional, ...)
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Optimized handling via custom TypeHandlers.
Collections
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Via generic handling logic (List, Set, Map, etc.).
Optimal handling required tailored TypeHandler (e.g. correctly handling loadFactor in java.util.HashMap)
Nested Collections
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JVM system-tied classes
(Thread, ClassLoader, WeakReference, ...)
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Technically handleable, but handling system-instances could cause fatal problems (e.g. start a Thread just from loading data), so it is intentionally disabled.
JVM external-tied classes
(IO-Streams, FileChannel, ...)
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Technically handleable, but external dependencies could cause fatal problems (e.g. existence of a referenced file), so it is intentionally disabled.
Java 5
Feature
Supported
Note
Enums
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Automatically handled as constant instances to maintain referential integrity / identity.
Enums with mutable state
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Enums anonymous subclasses
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Java 8
Feature
Supported
Note
Lambdas
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Type-handleable in theory. But JVM is not able to resolve its own type definitions for lambdas.
Java 14
Feature
Supported
Note
Records
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Records are mere syntax sugar for classes.

Last modified 1yr ago

Feature	Supported	Note
Classes
Classes without default constructor
Abstract classes / Interfaces		Perfectly handleable as types, but there can never be instances to be persisted in the first place.
Inner classes
Anonymous inner classes
Primitives
References
Final fields
Static fields		Not supported since they are outside of an entity graph / a database, i.e. potentially shared by multiple graphs.
Constant primitives		No sense in persisting those. These are just plain trivial values outside of an entity graph / a database.
Constant instances		Must be registered for loading to update them instead of creating independent new instances.
Primitive arrays
Object arrays
Multi dimensional arrays		Technically the same as object arrays as every array is an object itself.
JDK value types (String, Number types, Date, File, Locale, Optional, ...)		Optimized handling via custom TypeHandlers.
Collections		Via generic handling logic (List, Set, Map, etc.). Optimal handling required tailored TypeHandler (e.g. correctly handling loadFactor in java.util.HashMap)
Nested Collections
JVM system-tied classes (Thread, ClassLoader, WeakReference, ...)		Technically handleable, but handling system-instances could cause fatal problems (e.g. start a Thread just from loading data), so it is intentionally disabled.
JVM external-tied classes (IO-Streams, FileChannel, ...)		Technically handleable, but external dependencies could cause fatal problems (e.g. existence of a referenced file), so it is intentionally disabled.