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The correct solution to the exception has been solved, and the test is effective! ! !

The correct solution to the exception has been solved, and the test is effective! ! !

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Problem analysis

Reason for the error

Solution

Problem analysis

UnsupportedOperationException It is a runtime exception in Java.This exception is usually thrown when an unsupported operation is called, such as when trying to modify an immutable collection.

This exception is often encountered in Java collection frameworks, especially when usingOr similar tool class creates read-only views when modifying them.


	at (Unknown Source)
	at $(Unknown Source)
	at (Unknown Source)

 

Reason for the error

  1. Try to modify an immutable collection: for example, byThe resulting list is immutable, and any attempt to modify the list will cause this exception.
  2. Use custom collections with incomplete implementations: If you create a custom collection class and do not override all methods, the default implementation will usually throwUnsupportedOperationException。
  3. API limitations: Some API methods are designed to be read-only, and calling their modification methods (if they exist) will also throw this exception.

To resolve this exception, you first need to check the code context where the exception occurred and clarify which operation caused the problem. Depending on the situation, the following strategies can be adopted:

  1. If you are operating read-only collections, consider whether you should use a modifiable collection.
  2. For custom collection implementations, make sure that all necessary methods have been correctly covered.
  3. Confirm the API documentation to understand the behavior of the method and to confirm whether some read-only methods are called.

 

Solution

  • Replace immutable collections:If you need to modify the collection, you should use a variable collection, for exampleArrayListorHashMap。
  • Modify the custom collection class:If your custom collection class fails to override certain methods, provide a specific implementation to support the required actions.
  • Check API restrictions:Read the relevant API documentation to determine whether the method has been misused; if the method is designed to not support modification operations, do not try to modify it.
  • Exception handling:thrown in possibleUnsupportedOperationException Add exception handling logic around the code block.
  • Test code changes:After applying the above changes, thoroughly test the code to ensure that the modifications are valid and no new issues were introduced.

 

Summarize

Through the above steps, we can solve targeted solutions caused by attempting to perform unsupported operations. Exception, thus causing the program to run normally.

Remember to always read and understand the API documentation you are using and have an in-depth understanding of how Java collection framework works. This not only avoids such errors, but also improves your programming efficiency and code quality.

The above is the solution to the cause of this problem error. Welcome to leave a message in the comment area to discuss whether it can be solved.If this article is helpful to you, welcome focus on , like,collect,CommentOnly bloggers have the motivation to continue to record the problems they encounter! ! !

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