Nowadays, Java is one of the world’s most used object-oriented programming languages for its dependability and portability. To assist the self-studies of novice students, we have developed the Java programming learning assistance system (JPLAS). JPLAS offers several types of exercise problems for different difficulties, including the grammar-concept understanding problem (GUP), the mistake correction problem (MCP), the element fill-in-blank problem (EFP), and the phrase fill-in-blank problem (PFP), where a question asks to answer the corresponding keyword or phrase in the given source code. Unfortunately, some students cannot solve them well as the difficulty level is ascending. In this paper, to help such students, we propose a hint function that will show the first or more characters of each correct answer word in the answer interface on a web browser for JPLAS, when requested. The use of this function by a student can be traced by a teacher to analyze the performance and problem difficulty. For evaluations, we generated three instances for GUP, MCP, EFP, and PFP respectively, and assigned them to junior students taking the Java programming course in Okayama University, Japan. Their answer results found that the proposal is effective in helping students solve exercise problems in JPLAS, but the thinking time needs to be adjusted for PFP.