KNKhalid Najam
Selected work / 03Khalid Najam

Payroll development · 2022–2026

Payroll

Explore contributions to PeopleStrong’s payroll platform: features, calculations, approvals, and runtime upgrades across Java, Angular, and SQL.

Java EEAngularSQL ServerHibernateRESTWorkflowBigDecimalJDK 17

Role and context

Contribution
Full-stack features, calculation rules, approval workflows, and runtime upgrades.
Setting
PeopleStrong payroll platform · 2022–2026
Scope
Contributions to a wider platform built and maintained by the team.

The problem

Payroll changes have to preserve calculation accuracy, date rules, approvals, integrations, and existing customer workflows. New features and upgrades must account for those dependencies.

A closer look

Upgrading services without breaking payroll

Constraint
Formula execution, persistence, and existing customer workflows had to keep working during runtime upgrades.
Decision
Migration contributions covered JDK 17, WildFly, Rhino, and Hibernate 6.6 compatibility. Monetary calculations moved to BigDecimal and Java rules replaced Drools reimbursement validation.
Tradeoff
The work required checking formula and persistence behavior, not just getting the code to compile.
Not included
The eight-week delivery timeline applies to NPS V3. Regression rates, financial-error reductions, and platform-wide impact figures are not published here.

Explore the implementation

Feature development covered Loan, Investment V3, NPS V3, BRE, CTC, Variable Pay, and FBP, from database logic to REST APIs and Angular screens.

NPS V3 went from schema to production in eight weeks, including configuration, encrypted data handling, approvals, discontinuation, date rules, and employee self-service.

Java rules replaced Drools reimbursement validation, and monetary calculations moved from Double to BigDecimal.

Migration contributions included JDK 8 to JDK 17 and WildFly, Nashorn to Rhino, and Hibernate 6.6 compatibility fixes.

Additional work covered reimbursement APIs, mobile workflows, multilingual investment support, security fixes, and production incidents.

Architecture overview

View architecture
  1. Employee / admin UI

    Employees and administrators use screens for configuration, declarations, claims, and approvals.

  2. Service APIs

    APIs connect user actions and integrations to payroll services.

  3. Domain services

    Services handle payroll rules, calculations, validation, and status changes.

  4. Rules & calculation

    Calculation rules cover precision, eligibility, formulas, and dates.

  5. Workflow & state

    Approval and lifecycle changes are saved and validated.

  6. Data model

    The database stores payroll history, configuration, and audit records.

  7. External integrations

    APIs connect payroll with mobile applications, payment flows, and other systems.

Select a step to explore the flow.

Design decisions

Calculation precision

BigDecimal and currency-specific rounding are used for monetary calculations.

Approval workflows

The workflows cover approval, rejection, discontinuation, final settlement, and reopening.

Compatible upgrades

Runtime upgrades must preserve existing calculations, persistence behavior, and customer workflows.

Production support

Incident findings inform validation rules, diagnostics, and defaults.

Results & limits

Contribution scope

This work covers features and migrations within the wider payroll platform, not ownership of the entire platform. NPS V3 took eight weeks from schema to production; that is a project-specific timeline, not an average across releases.

Takeaway

Payroll upgrades need checks for existing date rules, rounding, permissions, and customer workflows.