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copied!<p>Your requirement to have <code>static</code> method doesn't leave much space for clean solution. One of the possible ways is to mix static and dynamic, and lose some CPU for a price of saving on RAM:</p> <pre><code>class Entity { private static final ConcurrentMap<Class, EntityMetadata> metadataMap = new ...; Entity(EntityMetadata entityMetadata) { metadataMap.putIfAbsent(getClass(), entityMetadata); } public static EntityMetadata getMetadata(Class clazz) { return metadataMap.get(clazz); } } </code></pre> <p>The way I would like more would be to waste a reference but have it dynamic:</p> <pre><code>class Entity { protected final EntityMetadata entityMetadata; public Entity(EntityMetadata entityMetadata) { this.entityMetadata=entityMetadata; } } class A extends Entity { static { MetadataFactory.setMetadataFor(A.class, ...); } public A() { super(MetadataFactory.getMetadataFor(A.class)); } } class MetadataFactory { public static EntityMetadata getMetadataFor(Class clazz) { return ...; } public static void setMetadataFor(Class clazz, EntityMetadata metadata) { ...; } } </code></pre> <p>You could get even get rid of <code>EntityMetadata</code> in <code>Entity</code> completely and leave it factory only. Yes, it would not force to provide it for each class in compile-time, but you can easily enforce that in the runtime. Compile-time errors are great but they aren't holy cows after all as you'd always get an error immediately if a class hasn't provided a relevant metadata part.</p>

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