Spring Boot NullPointerException in InlibraryController.AddNum() Method

The error message indicates that a NullPointerException occurred in the 'AddNum' method of the 'InlibraryController' class at line 50. This means that there is a null value being accessed or used inappropriately at that line, resulting in the exception.

To fix this issue, you need to identify the specific variable or object that is causing the null value and handle it accordingly. Check the code at line 50 of the 'InlibraryController' class and ensure that any variables or objects being accessed are properly initialized and not null. You may need to add null checks or initialize the variable correctly before using it.

Additionally, you can also debug the code to track the null value and identify the root cause of the issue. This can be done by setting breakpoints in your IDE and stepping through the code to see the values of variables and objects at each step.

Once you have identified and resolved the null value issue, the NullPointerException should no longer occur.