Hybrid memory, which leverages the benefits of traditional DRAM and emerging memory technologies, is a promising alternative for future main memory design. However popular management policies through memory-access recording and page migration may invoke non-trivial overhead in execution time and hardware space. We designed and implemented a management policy inside Java Virtual Machine for
hybrid memory (DRAM + NVM). Analysis of the memory access densities for heap
spaces is used to determine which spaces are mapped to fast memory avoiding
migration overhead. Objects that are identified as likely to cause high memory access
density are promoted to fast memory. Compared to OS management, performance is
improved up to 31%.