As a reliable, portable, and practical programming language, Java has been educated in many universities and professional schools. To assist Java educations, we have developed a Web-based Java Programming Learning Assistant System (JPLAS) to help students studying Java programming by themselves through automatic testing of Java source codes using the test-driven development (TDD) method. Unfortunately, JPLAS is not suitable for novice students taking basic Java classes, because they need to extract necessary information such as the names of classes and methods from a test code for automatic testing before writing a source code. Previously, we implemented the code design learning function in JPLAS to assist such students. In this paper, we propose a Javadoc hint function in JPLAS to further assist students by showing the detailed information that is automatically generated from the reference code by a teacher for the assignment. We verify the effectiveness of our proposal through an experimental use by 41 students in our department.