Is there a possible memory issue causing objects to stay in old generation for long ofbiz and javolution

[sharad bhushan <sh...@yahoo.co.in>]

Hello Everyone,

I have been trying to get the understanding of 
memory allocation when debugging the  load and memory issue in our ofbiz instance

Here is the snap shot of our gc log after three days of running and this had been continuing for next two days and went  low 
eventually not responding.   This Full GC run as below was continuous with tenured memory not clearing and Full GC kept running all
together for 2 days with breaks for few hours, it still survived  "out of memory" as young generation was releasing on Full GC.

328821.354: [Full GC 328821.354: [Tenured: 
1048576K->1048575K(1048576K), 2.9016030 secs] 
1520444K->1087815K(1520448K), [Perm : 49067K->49050K(49152K)], 
2.9017140 secs] [Times: user=2.90 sys=0.00, real=2.90 secs] 
328825.334: [Full GC 
328825.334: [Tenured: 1048575K->1048575K(1048576K), 2.4392020 secs] 1520447K->1097197K(1520448K), [Perm : 
49054K->49054K(49152K)], 2.4393150 secs] [Times: user=2.43 sys=0.00, 
real=2.44 secs] 
328828.673: [Full GC 328828.673: [Tenured: 1048575K->1048575K(1048576K), 2.4696630 secs] 1520447K->1107798K(1520448K), [Perm : 
49063K->49063K(49152K)], 2.4697760 secs] [Times: user=2.46 sys=0.00, 
real=2.46 secs] 

403173.352: [Full GC 403173.352: [Tenured: 
1048576K->1048576K(1048576K), 2.7718690 secs] 
1520447K->1252656K(1520448K), [Perm : 49417K->49417K(49664K)], 
2.7719880 secs] [Times: user=2.77 sys=0.00, real=2.77 secs] 
403176.958: [Full GC 403176.958: [Tenured: 1048576K->1048576K(1048576K), 
2.7772930 secs] 1520448K->1264672K(1520448K), [Perm : 
49421K->49421K(49664K)], 2.7774020 secs] [Times: user=2.78 sys=0.00, real=2.77 secs] 
403180.713: [Full GC 403180.713: [Tenured: 1048576K->1048576K(1048576K), 
2.7374900 secs] 1520447K->1267832K(1520448K), [Perm : 
49426K->49426K(49664K)], 2.7376110 secs] [Times: user=2.73 sys=0.00, 
real=2.74 secs] 

With above said i would like to give the top 
classes on doing jmap -histo
javolution FastMap$Entry - ~240MB - 
nearly 4,900,000 objects
javolution FastMap$Entry[]  - ~120MB 
javolution HashMap$Entry - ~90MB  

The java max heap  (-Xmx) is 1.5GB. 

the tenured - old gen is ~1000MB and the above three elements are 50% 
occupied, certainly after drilling through few heap dumps it describes 
of above three classes.

The tenured space does not get cleared, I am looking to suspect the FastMap, specifically, we have been using ofbiz cache too.

Can there be 
any inputs or observation about the possible issue in memory or javolution, any directions for the 
above description would certainly help me.

Regards
Sharad