Summary: Traditional Java code generation and instruction fetch path is not efficient, as Java binary code is typically written into the data cache first, and then is loaded into the instruction cache through the shared L2 cache or memory, which takes both time and energy. In this paper, we study three hardware-based code caching strategies, which attempt to write and read the dynamically generated Java code faster and more energy-efficiently. Our experimental results indicate that with proper architectural support, writing code directly into the instruction cache can improve the performance for a variety of Java applications by 9.6\% on average, with up to 42.9\%. Also, the average energy dissipation of these Java programs can be reduced by 6\% with efficient code caching.