Code documentation is essential to improve software maintainability and comprehension. The tedious nature of manual code documentation has led to much research on automated documentation generation. Existing automated approaches primarily focused on code summarization, leaving a gap in template-based documentation generation (e.g., Javadoc), particularly with publicly available Large Language Models (LLMs). Furthermore, progress in this area has been hindered by the lack of a Javadoc-specific dataset that incorporates modern language features, provides broad framework/library coverage, and includes necessary contextual information. This study aims to address these gaps by developing a tailored dataset and assessing the capabilities of publicly available LLMs for context-aware, template-based Javadoc generation. In this work, we present a novel, context-aware dataset for Javadoc generation that includes critical structural and semantic information from modern Java codebases. We evaluate five open-source LLMs (including LLaMA-3.1, Gemma-2, Phi-3, Mistral, Qwen-2.5) using zero-shot, few-shot, and fine-tuned setups and provide a comparative analysis of their performance. Our results demonstrate that LLaMA 3.1 performs consistently well and is a reliable candidate for practical, automated Javadoc generation, offering a viable alternative to proprietary systems.