What are common challenges Java API developers face when integrating APIs with legacy systems?

Java API Developers often encounter challenges when connecting modern APIs to legacy systems, such as dealing with outdated protocols, inconsistent data formats, and limited documentation. Overcoming these issues usually requires careful planning, thorough testing, and sometimes the development of custom adapters or middleware. Working closely with system architects and stakeholders is essential to ensure compatibility and minimize disruptions, while maintaining security and performance standards.