Employee Management System

Project Overview

The Employee Management System is a comprehensive Spring Boot REST API application that manages employee records, department hierarchy, salary processing, attendance tracking, and leave management. It implements full CRUD operations with advanced features like search/filter, pagination, role-based access control, and report generation.

This project is ideal for:

• Java developers learning Spring Boot and REST API development
• Students building portfolio projects for campus placements
• Developers preparing for Spring Boot developer interviews
• Anyone wanting to understand enterprise application architecture

The system supports three user roles (Admin, HR Manager, Employee) with different access levels, implements comprehensive validation, and follows industry-standard design patterns (Repository, Service, DTO).

Features

1. Employee CRUD — Create, Read, Update, Delete employee records with validation
2. Department Management — CRUD for departments with manager assignment
3. Search & Filter — Search employees by name, email, department, designation
4. Pagination & Sorting — Efficient data retrieval with configurable page size
5. Role-Based Access — Admin (full), HR Manager (read/write), Employee (read own)
6. Salary Management — Monthly salary processing with allowances and deductions
7. Attendance Tracking — Daily check-in/check-out with work hours calculation
8. Leave Management — Apply, approve/reject leave with balance tracking
9. Department Hierarchy — Parent-child department structure with org chart
10. Employee Onboarding — New hire workflow with document checklist
11. Performance Reviews — Annual/quarterly review submission and tracking
12. Report Generation — Excel and PDF reports for HR analytics
13. Email Notifications — Welcome email, leave approval, salary slip
14. Bulk Import — Upload employees via CSV/Excel file
15. Audit Trail — Track all modifications with who/when/what
16. Profile Photo — Upload and manage employee profile pictures
17. Dashboard Stats — Total employees, department-wise count, recent joins
18. Designation Management — Configure job titles and bands
19. Emergency Contacts — Store employee emergency contact details
20. Document Management — Upload and store employee documents (ID, certificates)

Project Structure

Database Schema

employees Table

departments Table

attendance Table

leaves Table

salaries Table

Entity Relationships

Key Code Snippets

Employee Entity

Employee Repository

Employee Service Implementation

Employee Controller

API Endpoints

Sample Request & Response

POST /api/v1/employees

Request:

Response (201 Created):

How to Run

Prerequisites

• Java 17+, Maven 3.9+, MySQL 8.0

Step-by-Step

Step 1: Clone

Step 2: Create Database

Step 3: Configure application.yml

Step 4: Build & Run

Step 5: Access

• API: http://localhost:8080/api/v1
• Swagger: http://localhost:8080/swagger-ui.html
• Default Admin: admin@company.com / Admin@123

Screenshots Description

1. Swagger UI — All employee endpoints with request/response schemas
2. Create Employee — POST request with validation error examples
3. Employee List — Paginated response with sorting options
4. Search Results — Keyword search matching name and email
5. Dashboard Stats — Total employees, department distribution chart data
6. Attendance Report — Monthly calendar view with present/absent/leave markers
7. Leave Management — Leave application form and approval workflow
8. Salary Slip — Monthly salary breakdown with allowances and deductions

Future Enhancements

1. Biometric Integration — Fingerprint-based attendance marking
2. Org Chart Visualization — Interactive organizational hierarchy
3. Employee Self-Service Portal — React frontend for employees
4. Training Management — Track employee training and certifications
5. Recruitment Module — Job postings, applications, interview scheduling
6. Expense Management — Submit and approve expense claims
7. Multi-tenant Support — Serve multiple companies from one instance
8. Mobile App — Flutter-based mobile attendance and leave app
9. Analytics Dashboard — Attrition prediction, salary benchmarking
10. Integration APIs — Connect with HRMS tools like SAP, Workday

Interview Questions

Q1: How do you implement pagination and sorting in Spring Boot?

Answer: Spring Data JPA provides Pageable interface. In the controller, we accept page, size, sortBy, sortDir parameters. We create PageRequest.of(page, size, Sort.by(sortBy).ascending()) and pass it to repository methods that return Page<Entity>. The response includes content, totalElements, totalPages, hasNext. This ensures we never load all records into memory — only the requested page is fetched with SQL LIMIT/OFFSET.

Q2: Why use soft delete instead of hard delete for employees?

Answer: Hard delete causes referential integrity issues (attendance records, salary history point to deleted employee). Soft delete (setting status to RESIGNED/TERMINATED) preserves historical data for audit/compliance, allows data recovery, and maintains FK relationships. We use @Where(clause = "status != 'RESIGNED'") annotation or custom queries to exclude soft-deleted records from normal queries.

Q3: How do you handle the DTO pattern in this project?

Answer: We separate the API layer from the database layer using DTOs. EmployeeCreateRequest has only fields needed for creation (with @Valid annotations). EmployeeResponse excludes sensitive fields (password) and flattens relationships (shows department name, not the full Department object). MapStruct auto-generates the mapping code at compile time, which is faster than reflection-based mappers like ModelMapper.

Q4: How is the salary calculation implemented?

Answer: Basic = 40% of CTC, HRA = 50% of Basic, DA = 10% of Basic, Special Allowance = remaining. Deductions: PF = 12% of Basic (capped at ₹1800), Professional Tax = ₹200, TDS calculated based on slab. net_salary = (basic + hra + da + special) - (pf + pt + tds). The SalaryService.processMonthly() method iterates all active employees, calculates components, and creates Salary records in bulk.

Q5: How do you secure the APIs with role-based access?

Answer: Spring Security with JWT: (1) User logs in, receives JWT token, (2) Token contains user role claim, (3) SecurityFilterChain validates token on each request, (4) @PreAuthorize("hasRole('ADMIN')") on controller methods restricts access, (5) Custom AccessDeniedHandler returns 403 with proper message. We also implement method-level security so employees can only view their own data.

Q6: How would you implement bulk employee import from Excel?

Answer: We use Apache POI to read .xlsx files: (1) Controller accepts MultipartFile, (2) Service reads each row, validates data (email format, required fields, no duplicates), (3) Collects errors per row without failing entire import, (4) Uses saveAll() with batch processing for valid rows, (5) Returns summary: {imported: 45, failed: 3, errors: [{row: 7, field: "email", message: "duplicate"}]}. We set spring.jpa.properties.hibernate.jdbc.batch_size=50 for efficient batch inserts.