Your dump files are most likely being generated because you have processes running out of heap memory. You need to analyze the dump file to figure out which one and increase the memory setting for them if possible.
You may need to increase the heap size for Tomcat.
I added something to our configuration that includes the process ID in the log file names. This has helped to identify which process generated the heap dump because there will be the same process ID in the heap dump file as in the process log file. I can’t for the life of me find where I made the change or the documentation that caused me to make the change.
I’ll probably run across when I’m not trying to find it.