feat: Add practical real-world examples for Singleton, Builder, and S…#3398

gurioh wants to merge 1 commit intoiluwatar:masteriluwatar/java-design-patterns:masterfrom

gurioh:claude/requirements-analysis-011CV4xvZGXx8DVU17fH6sofgurioh/java-design-patterns:claude/requirements-analysis-011CV4xvZGXx8DVU17fH6sofCopy head branch name to clipboard