Java Desktop Developer (Freelance short term project)

Job description

Company Description
Invito Software Solutions is a leading software development company providing world-class web and mobile solutions efficiently and cost-effectively.

We specialize in next-generation design patterns, responsive coding techniques, and rigorous quality assurance, resulting in high-quality apps with a high return on investment.

Our scalable services and customized engagement models cater to businesses of all sizes, from innovative startups to well-established companies.

We develop powerful and effective solutions that meet our clients' specific needs.
Project: Spring-Powered Desktop App for Invoice OCR → Clean CSVWhat you’ll build
Desktop Java application (Java 17+) backed by Spring Boot
Runs locally  (offline-first), ships as a single native installer or fat JAR.
UI options (pick one):
JavaFX UI  using Spring for DI (FXML controllers wired via Spring).
Swing UI  with Spring-managed services.
Embedded local web UI : Spring Boot serves a UI (e.g., Vaadin or lightweight HTML/TS), shown in an embedded browser (WebView/JxBrowser).
Invoice ingestion : drag-and-drop folders/files; PDF, PNG/JPG; multipage; batch mode.
AI/OCR pipeline  (pluggable via Spring beans):
Local OCR (Tesseract) + layout/zone analysis, or
Cloud OCR (AWS Textract, Google Vision) with retry/backoff, or
LLM-assisted parsing to a JSON schema with guardrails.
Field extraction  (headers + line items): vendor, invoice #, dates, currency, taxes, subtotals/totals, PO, line descriptions, qty, unit price, amounts.
Validation & review UI : show the document preview, highlight extracted zones, flag low-confidence fields, quick edits, autocomplete.
CSV export : stable schema; normalize number/date/locale; export per file or batch.
Rules & heuristics : vendor templates, regex fallbacks, learned patterns, per-vendor overrides.
Quality metrics : confidence per field, accuracy dashboards, reject reasons, simple analytics.
Offline by default , with  optional cloud connectors  for OCR/LLM and template sync.
Architecture (Spring-centric) App launcher : desktop entry point that bootstraps  SpringApplication .
Core modules (Spring beans) :
IngestionService: drag-and-drop, PDF/image decoding, page splitting.
OcrService (strategy): TesseractOcrService, TextractOcrService, GcvOcrService.
ParsingService: layout analysis, key-value detection, tables; optional LlmParsingService.
TemplateService: vendor profiles, regex rules, learned mappings; local cache + optional remote sync.
ValidationService: confidence scoring, anomaly detection, suggestions.
ExportService: CSV writer (stable schema, locale normalization).
MetricsService: capture confidence, errors, durations; local storage (SQLite/H2).
DocumentPreviewService: render + zone overlays (PDFBox + image layers).
Persistence : Spring Data (SQLite/H2 on disk) for runs, templates, audits.
Config : Spring profiles (offline, cloud), YAML config for OCR provider keys, thresholds, CSV schema.
UI layer :
If  JavaFX : Controllers get beans via Spring (custom SpringFXMLLoader), reactive updates via ApplicationEventPublisher.
If  Swing : @Component panels wired to services, event bus for updates.
If  Vaadin (embedded web) : served by Spring Boot; package app with an embedded browser window.
Key user flows Drop files/folders  → Ingestion queue (progress bar, cancel/retry).
OCR + Parsing  → Field map + line items + confidence per field.
Review screen  → Document preview with highlight boxes, editable fields, low-confidence badges, autocomplete from templates.
Approve/Reject  → Approved go to export queue; rejected capture reasons.
Export  → Single CSV or per-invoice CSV; schema versioning; logs.
Analytics  → Success rate, average confidence, common reject reasons, vendor leaderboard.
CSV schema (stable, versioned) schemaVersion, fileId, vendorName, invoiceNumber, invoiceDateISO, dueDateISO, currency, subtotal, tax, total, poNumber, …
Line items (denormalized or separate CSV): lineIndex, description, qty, unitPrice, amount.
Locale-safe formatting (ISO dates, dot decimal).
Offline/Cloud strategy Offline : Tesseract + local templates; everything runs without internet.
Cloud (optional) : switch OCR/LLM beans via Spring profile/env; graceful fallback to offline if unavailable.
Packaging & ops Distribution : jpackage/native installers (Win/MSI, macOS/DMG, Linux/DEB/RPM) or fat JAR.
Logging : Spring Boot logging; per-invoice audit trail; export logs.
Updates : optional auto-update check (profile-gated).
Security & privacy Local processing by default; redact PII in logs; encrypted at-rest store (configurable).
For cloud calls: minimal payloads, signed requests, regional endpoints.
Nice-to-haves Hot keys and batch review UX.
Template “learn” button: convert manual fixes into a saved vendor rule.
Import/export of templates.
Headless CLI mode: --input dir --output csv.
Deliverables Source code (Spring Boot project + UI layer).
Packaged desktop installer(s).
Sample vendor templates & test invoices.
README + setup, profiles, and OCR provider docs.
Test suite (unit + a few end-to-end fixtures).
Short user guide (drop → review → export).
Qualifications Strong proficiency in  Java  and  Spring Boot  (DI, Spring Data, configuration, profiles).
Experience building  desktop UIs  in  JavaFX ,  Swing , or  Vaadin  (served by Spring) with responsive, user-friendly design.
Skilled in troubleshooting, debugging, and performance tuning in Spring/Java.
Familiar with OCR/AI integrations (Tesseract, Textract, Vision, OpenAI/Vertex) and robust parsing.
Version control with Git; excellent communication; ability to work independently/remote.
Bachelor’s in CS/Engineering (or equivalent experience).
Freelance/contract experience is a plus.

Required Skill Profession

Computer Occupations