Do the following:

• Ensure that your ThreadPoolTaskExecutor is properly configured to handle multiple concurrent tasks. By default, the thread pool might not be configured optimally for your use case.

• Ensure that your ThreadPoolTaskExecutor is properly configured to handle multiple concurrent tasks. By default, the thread pool might not be configured optimally for your use case.

• Add logging to verify that tasks are being executed concurrently. This will help you debug and understand the flow of execution.

• Ensure that the controller method is correctly waiting for all futures to complete.