It's the Java process:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
32215 zimbra 20 0 470m 28m 12m R 43.8 2.8 0:01.54 java
25416 zimbra 20 0 689m 203m 38m S 2.0 20.1 2:35.20 java
32244 zimbra 20 0 4776 1288 1028 S 0.7 0.1 0:00.02 zmantispamctl