What are the disadvantages of the implemented solution for the ATM?

It is difficult to give an exact answer without specific code, but typical drawbacks of solutions for ATMs in Java may include:

• Lack of error and exception handling — for example, not considering situations with insufficient funds or network failures.
• Poor modularity and extensibility — if the code is monolithic, it is difficult to add new features (e.g., support for different currencies).
• Insufficient security — lack of data encryption, authentication checks.
• Tight coupling of components — for example, the interface directly depends on the logic, which complicates testing.
• Lack of logging and auditing — important functions for banking applications.

To improve, it is recommended to use design patterns (e.g., MVC), implement exception handling, separate responsibilities among classes, and ensure data security.