Empirical Analysis of Common Pitfalls for Novice Programmers When Learning Java Generics

Java generics is a core language feature for implementing compile-time type safety and improving code reusability. Nevertheless, novice programmers frequently face confusing compilation failures and unexpected runtime exceptions when learning generics. These obstacles mainly stem from insufficient understanding of type erasure, wildcard variance rules, and special subtyping mechanisms for generic parameterized types. This paper conducts an empirical analysis of typical pitfalls encountered by beginner Java learners. We collect and categorize error records from undergraduate programming assignments, summarize root causes for each kind of mistake, and quantify the frequency distribution of different misconceptions. Experimental statistics show that misunderstanding of type erasure, misuse of wildcards, and unsafe generic casting mixed with raw types constitute the top-three most frequent problems. Based on empirical findings, we propose targeted teaching suggestions and practice cases to reduce learning barriers and help students build correct mental models for Java generics.