Allocation failure in Java

Question

I have a method which hits DB and fetches lot of records into memory for processing. After I fetch the records and before I start processing, I get the following log message. What does it mean ?

164575.034: [GC (Allocation Failure)  4937664K->3619624K(5602816K), 0.0338580 secs]

Options:

java.opts=-d64 -Xmx8g -XX:+PrintGCTimeStamps -verbose:gc -XX:MaxPermSize=512m -XX:+UseParallelGC -XX:+UseParallelOldGC

Answer 1

It just basically tells you that it had to run GC to allocate additional memory, it does not fit in memory otherwise. So it is just a reason for GC.