Hi, attached are 5 patches with slightly performance improvements and noticable max memory reductions. free_mem_earlier_v1: The coords map is released before the hooks are started. The coords are used only while the input data is loaded. Additionally all hooks release their data at the end of their end() method. I measured the maximum memory usage by compiling a big tile and minimizing the -Xmx parameter so that no OutOfMemoryError occurred. Using the patch I could compile the big tile with 9% less memory. free_nodes_ways_earlier_v1: All OSM nodes and ways were removed only after they have been completely converted. This patch releases each OSM object just after it has been converted to the intermediate MapElement object. tags_v1: This patch removes some autoboxing (Integer to int) from heavily used methods. I don't know if there still is a penalty for autoboxing with current JREs. But it feels better not to use autoboxing. polyline_addpoints_v1: Instead of adding point by point to a polyine the patch adds full list of points. Arraylists containing the points need to be resized once only instead of multiple times. clipping_v1: The makeBoundaryNodes method clips all ways to the bounding box. But it has to workout all nodes if the way is completely withing the bbox. The patch avoids that. WanMil