What are the scenarios in which the Java Chain of Responsibility pattern is applied?

There are several application scenarios for the Java Chain of Responsibility pattern:

1. Log processing: When it is necessary to handle logs, filter and classify them according to certain rules, the Chain of Responsibility pattern can be used. Each handler is responsible for processing a certain type of log; if it cannot handle the log, it is passed on to the next handler.
2. Filter chain: When a series of filtering operations is needed for a request, the chain of responsibility pattern can be used. Each filter is responsible for performing a specific filtering operation, and if a filter is unable to handle it, the request is passed on to the next filter.
3. Chained calls: When a series of methods need to be called in a specific order, the chain of responsibility pattern can be used. Each method is responsible for performing a specific operation, and if one method is unable to handle it, the request is passed on to the next method.
4. Error handling: When dealing with a series of possible errors, the Chain of Responsibility pattern can be used. Each handler is responsible for handling a specific type of error, and if a handler is unable to handle it, the error is passed on to the next handler.
5. Message processing: The Chain of Responsibility pattern can be used when a series of different types of messages need to be handled. Each handler is responsible for processing a specific type of message, and if a handler is unable to process the message, it is passed on to the next handler.

In conclusion, the Chain of Responsibility pattern is suitable for scenarios requiring requests or operations to be handled in a specific order, with each handler responsible for processing only the part it is capable of handling.