The Loan Scheduling and Demand Processing Engine is a backend financial computation system responsible for generating amortization schedules, managing EMI demand creation, and handling overdue (OD) calculations across the loan lifecycle. The system computes principal and interest components using reducing-balance formulas and supports configurable parameters such as tenure, interest rate, moratorium period, grace days, and penalty structures. The engine dynamically generates repayment schedules at disbursement and creates demand entries on scheduled dates via batch jobs. It supports advance payments, part-payments, foreclosure, redraw logic, and restructuring scenarios. Overdue calculations include penal interest, late fees, and daily accrual logic based on configurable business rules. The application is built using Java 11/17 with Spring Boot in a microservice architecture. Business logic is encapsulated in service layers with transactional consistency. Hibernate ORM is used for mapping domain models to PostgreSQL, ensuring ACID-compliant financial updates. Scheduled jobs and Spring Batch handle periodic demand generation and overdue marking. Apache Kafka is used for publishing loan and collection events to downstream systems. The system is optimized for high-volume loan portfolios with efficient indexing, minimal query complexity, and stateless REST APIs, ensuring scalability, reliability, and maintainability.