How Can I Handle @Lob Lazy Loading and OutOfMemoryErrors in Spring and Hibernate?

Spring, Hibernate, Blob Lazy Loading: A Discussion

In Hibernate, the @Lob annotation is used to specify a persistent property that contains a large object, such as a BLOB or CLOB. By default, @Lob properties are fetched lazily, meaning that they are only retrieved from the database when they are actually accessed in code.

Lazy loading of @Lob properties can help to improve performance by reducing the amount of data that is loaded into memory when an object is retrieved from the database. However, in some cases, lazy loading of @Lob properties can lead to OutOfMemoryError exceptions, especially when the @Lob property contains a large amount of data.

One possible workaround for this issue is to use a "fake" one-to-one mapping instead of a @Lob property. This involves creating a new class that references the same table and primary key as the original class, but only contains the @Lob property as a property. The mapping between the two classes is specified as a one-to-one mapping with fetch="select" and lazy="true".

By using a "fake" one-to-one mapping, the @Lob property will only be retrieved from the database when it is actually accessed in code, which can help to improve performance and avoid OutOfMemoryError exceptions.

Additional Considerations:

• Some users have reported that lazy loading of @Lob properties does not work with all drivers and databases.
• Using bytecode instrumentation (such as Javassist or CGLib) may be necessary to enable lazy loading of @Lob properties with certain drivers and databases.
• The documentation for Hibernate does not provide clear guidance on the lazy loading behavior of @Lob properties, which can lead to confusion and frustration among developers.

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