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Learn how to efficiently add a `BigDecimal` to a list using Spring Expression Language, avoiding constructor issues with step-by-step guidance.
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This video is based on the question https://stackoverflow.com/q/62771421/ asked by the user 'MartinKnopf' ( https://stackoverflow.com/u/1511960/ ) and on the answer https://stackoverflow.com/a/62795273/ provided by the user 'winne2' ( https://stackoverflow.com/u/1301373/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Use Spring Expression Language to Add Objects to a List Without a Constructor

When working with Spring Expression Language (SpEL) and lists, you may encounter unexpected challenges, particularly when trying to add elements like BigDecimal without a constructor. If you find yourself facing frustrations when trying to manipulate lists, you're not alone! In this guide, we'll dive into the problem, the solutions available to you, and how to effectively manage list entries using SpEL.

The Problem: Adding a BigDecimal to a List

In your Java application, you might need to add instances of BigDecimal to a list using SpEL. Consider the following code snippet:

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In this example, while attempting to add a BigDecimal to the list using the line values[0], you're likely to run into an error like this:

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This indicates that there is no way to instantiate a BigDecimal when the list is empty, as SpEL expects a constructor to exist for this operation.

Solution: Setting the Whole List Instead

Fortunately, there’s an easy workaround to avoid this issue. Instead of targeting individual indices of the list, you can set the entire list at once. Here's how you can modify your approach:

Adjusting Your Approach

Set the Whole List: Instead of targeting a specific index like values[0], you can set the entire list. Change your code from:

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to:

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Adding Multiple Values: You can also add multiple values efficiently at once. For example:

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By setting the entire list with these expressions, no constructor issues arise, and you can smoothly add BigDecimal entries into your list.

Benefits of Using this Approach

No Constructor Issues: By setting the whole list, you avoid errors related to non-existing constructors.

Enhanced Readability: This method simplifies your code, making it easier to read and maintain.

Scalability: Easily add multiple items at once, which is more efficient than inserting them one by one.

Conclusion

When working with Spring Expression Language, managing lists can be tricky, especially with immutable objects like BigDecimal. However, by using the approach of setting the entire list rather than individual indices, you can sidestep constructor limitations and make your code more effective and comprehensible.

Now that you have this solution, you can confidently handle adding objects to lists in your Java applications using SpEL!