Скачать или смотреть Resolving the OutOfMemoryError in iText PDF Processing

Discover effective solutions for handling `OutOfMemoryError` when reading PDFs with iText 5.5.0 in Java. Learn how to adjust JVM heap settings to resolve memory issues effortlessly.
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This video is based on the question https://stackoverflow.com/q/70398661/ asked by the user 'Parameswar' ( https://stackoverflow.com/u/1081319/ ) and on the answer https://stackoverflow.com/a/70518575/ provided by the user 'Lonzak' ( https://stackoverflow.com/u/2311528/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the OutOfMemoryError in iText for PDF Reading

When working with large PDF files, developers often face unexpected challenges, such as the notorious OutOfMemoryError. This issue can be particularly frustrating when the same code that once executed seamlessly begins to throw exceptions after a system upgrade or configuration change. In this post, we will explore the problem of getting OutOfMemoryError while using the PdfReader class from iText version 5.5.0, and provide practical solutions to resolve it.

The Problem Encountered

A user faced an OutOfMemoryError while trying to read a 20 MB PDF using iText in their Java application. Here’s a snippet of the error for context:

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

This error suggests that the Java Virtual Machine (JVM) has run out of memory and can no longer allocate space for new objects. The user noted that this issue did not arise on their previous PC, leading to speculation about changes in memory configuration after an upgrade.

Error Details

Error Type: OutOfMemoryError

Cause: Insufficient heap memory allocation

PDF File Size: 20 MB

The user attempted to resolve the issue with existing configurations in IntelliJ, but the problem persisted, making it clear that further adjustments were necessary in their JVM settings.

Exploring the Solution

Step 1: Increase Heap Memory Allocation

One of the most effective solutions to resolve the OutOfMemoryError is to increase the JVM heap size. By modifying the memory settings, you give the application more room to operate, which is especially critical when dealing with larger files.

Access JVM Options: In IntelliJ, navigate to the place where you can adjust the JVM options.

Modify Memory Settings: Change the maximum heap size flag (-Xmx) to a higher value. Here are some recommended values:

From -Xmx820m to -Xmx1500m

Alternatively, consider setting -Xmx2048m for even greater capacity if your system allows it.

These changes can be made directly in the configuration or by using command-line parameters as you launch your application.

Step 2: Optimize Code Cache Size

Additionally, the user was advised to reconsider the size of the code cache. The original configuration set the reserved code cache size to 1024 MB, which might be excessive for typical applications. Reducing this can free up memory for the heap. Here’s how to adjust it:

Change Code Cache Size: Modify the parameter as follows:

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

For even more efficiency, consider setting it to:

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

Monitor the Cache Usage: Use tools like jconsole to monitor the code cache section and determine the required size based on actual usage.

Final Steps: Testing and Validation

Once you have made the adjustments, run your application again to verify that the OutOfMemoryError has been resolved.

Ensure to handle any other possible memory-related issues that might arise depending on the complexity and size of the PDF files you are working with.

Conclusion

Memory management is a pivotal aspect of Java application development, particularly when handling large files like PDFs. By increasing your heap memory allocation and optimizing the code cache size, you can mitigate the risk of encountering OutOfMemoryError. If you find yourself facing similar issues, remember to revisit your JVM configurations, adjust as needed, and monitor the performance to ensure your application runs smoothly.

Now you can confidently process large PDFs using iText without facing memory constraints!