У вас заканчивается куча.
Increase heap memory available to JVM using Xmx argument.
Более подробная информация об этой ошибке (взято из here):
The detail message "GC overhead limit exceeded" indicates that the garbage collector is running all the time and Java program is making very slow progress. After a garbage collection, if the Java process is spending more than approximately 98% of its time doing garbage collection and if it is recovering less than 2% of the heap and has been doing so far the last 5 (compile time constant) consecutive garbage collections, then a java.lang.OutOfMemoryError is thrown. This exception is typically thrown because the amount of live data barely fits into the Java heap having little free space for new allocations. Action: Increase the heap size. The java.lang.OutOfMemoryError exception for GC Overhead limit exceeded can be turned off with the command line flag -XX:-UseGCOverheadLimit.
Вы можете попробовать другую структуру отображения, например Orika
Просто примечание: последнее обновление библиотеки Dozer было 04/2014. Возможно, вы должны использовать другую библиотеку сопоставления. – dit