How to Fix StackOverflowError When Using H2 Database in Spring Boot

Discover how to resolve the frustrating `StackOverflowError` that may occur when your Spring Boot application interacts with H2 Database. Learn the underlying causes and the simple solution.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: H2 intermittently experiencing a StackOverflowError when first hitting the database

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Resolving StackOverflowError in H2 Database with Spring Boot

If you're a Java developer working with Spring Boot and the H2 database, you may encounter an intermittent issue known as the StackOverflowError. This problem usually occurs when your application tries to execute a simple SELECT query during startup, causing frustration as your application requires several restarts to eventually function. Let's delve into the details of this problem and explore how to fix it.

Understanding the Problem

The StackOverflowError in our context is thrown by the H2 database (version 1.4.199). Here's a brief breakdown of the situation:

What happens: On startup, your application attempts to connect to the H2 database and execute a straightforward query, but it unexpectedly encounters a StackOverflowError.

Symptoms: The application fails to connect initially, logging the stack trace of the error, then succeeding after multiple restart attempts.

Underlying concerns: There's an error in the application logs stating file length -1 read length 768, which raises questions about data integrity.

The core of the issue seems to reside in how H2 manages recursion when hitting a threshold related to the database size or complexity - and this problem can be particularly pertinent when using large data types like CLOBs.

Breakdown of the Solution

Fortunately, a resolution exists for the StackOverflowError encountered in H2. The fix involves adjusting the stack size on the Java Virtual Machine (JVM). Let’s go over the steps to implement this solution:

Increasing the JVM Stack Size

Given that the default stack size may not suffice for your application’s complexity and data size, follow these steps:

Locate the JVM Options:
Depending on your IDE or deployment method (such as Spring Boot), locate where you can set JVM arguments.

Set the stack size:
Add the following argument to increase the stack size to 10MB:

[[See Video to Reveal this Text or Code Snippet]]

Why This Works

Recursion Depth: By increasing the stack size from the default of 256K to 10MB, we provide the H2 database engine with enough space to complete its recursive logic without running out of stack memory.

Error Causes: The initial StackOverflowError can wrap various other exceptions, such as IllegalStateException. This means that when the root cause (the StackOverflowError) is resolved, other symptoms are likely to disappear as well.

Alternative issues

In addition to the StackOverflowError, other exceptions you might encounter due to this root issue include:

Connection Errors: For example, an error stating "Unable to connect to H2".

State Errors: Such as "This store is closed" or "Reading from H2 file failed".

Conclusion

In summary, if your Spring Boot application intermittently throws a StackOverflowError when interacting with an H2 database, increasing the stack size to 10MB can often resolve this frustrating issue. This understanding of the problem allows developers to ensure smoother application startups and reliable database connectivity.

If problems continue even after this adjustment, further investigation into database file size, configurations, and H2 updates may be required.

By following the outlined steps, you can potentially save yourself from the hassle of constant application restarts and have a more reliable data access layer for your applications!