we have a huge problem with our J2EE application.
Every day at 11am, our application starts to be very slow because of the garbage collector's activity.
We don't have any batch tasks that runs at that hour but we have a particular functionality (written using Spring Integration framework) used to merge a large number of files (.pdf, .doc, ...) but we've already checked that all the streams are closed after the end of the process.

Please find below some logs about the garbage collector activity:

```
2015-04-30T11:00:59.752+0200: 15957.260: [GC-- [PSYoungGen: 620734K->620734K(638336K)] 2017070K->2018870K(2036480K), 0.1506240 secs] [Times: user=0.19 sys=0.00, real=0.15 secs] 
2015-04-30T11:00:59.902+0200: 15957.411: [Full GC [PSYoungGen: 620734K->45503K(638336K)] [ParOldGen: 1398136K->1398119K(1398144K)] 2018870K->1443622K(2036480K) [PSPermGen: 307483K->307454K(307776K)], 1.4963560 secs] [Times: user=2.65 sys=0.00, real=1.50 secs] 
2015-04-30T11:01:02.271+0200: 15959.779: [Full GC [PSYoungGen: 622271K->46624K(638336K)] [ParOldGen: 1398122K->1398142K(1398144K)] 2020393K->1444767K(2036480K) [PSPermGen: 307456K->307456K(307776K)], 1.2484490 secs] [Times: user=2.18 sys=0.00, real=1.25 secs] 
2015-04-30T11:01:04.181+0200: 15961.690: [Full GC [PSYoungGen: 576768K->45206K(638336K)] [ParOldGen: 1398143K->1398130K(1398144K)] 1974911K->1443337K(2036480K) [PSPermGen: 307456K->307456K(307776K)], 1.2151760 secs] [Times: user=2.13 sys=0.00, real=1.21 secs] 
2015-04-30T11:01:05.958+0200: 15963.466: [Full GC [PSYoungGen: 576768K->47369K(638336K)] [ParOldGen: 1398130K->1398123K(1398144K)] 1974898K->1445493K(2036480K) [PSPermGen: 307456K->307456K(307776K)], 1.2177990 secs] [Times: user=2.13 sys=0.00, real=1.21 secs] 
2015-04-30T11:01:07.782+0200: 15965.291: [Full GC [PSYoungGen: 576768K->46062K(638336K)] [ParOldGen: 1398123K->1398136K(1398144K)] 1974891K->1444199K(2036480K) [PSPermGen: 307460K->307460K(307776K)], 1.2808160 secs] [Times: user=2.25 sys=0.00, real=1.28 secs] 
2015-04-30T11:01:09.682+0200: 15967.191: [Full GC [PSYoungGen: 576768K->46868K(638336K)] [ParOldGen: 1398136K->1398143K(1398144K)] 1974904K->1445012K(2036480K) [PSPermGen: 307460K->307460K(307776K)], 1.2058500 secs] [Times: user=2.11 sys=0.00, real=1.21 secs] 
2015-04-30T11:01:11.588+0200: 15969.097: [Full GC [PSYoungGen: 576768K->50009K(638336K)] [ParOldGen: 1398144K->1398142K(1398144K)] 1974912K->1448152K(2036480K) [PSPermGen: 307469K->307469K(307776K)], 1.3628080 secs] [Times: user=2.39 sys=0.00, real=1.36 secs] 
2015-04-30T11:01:13.616+0200: 15971.124: [Full GC [PSYoungGen: 576768K->47592K(638336K)] [ParOldGen: 1398142K->1398099K(1398144K)] 1974910K->1445691K(2036480K) [PSPermGen: 307469K->307467K(307776K)], 1.6644920 secs] [Times: user=2.95 sys=0.00, real=1.67 secs] 
2015-04-30T11:01:16.046+0200: 15973.555: [Full GC [PSYoungGen: 576768K->49560K(638336K)] [ParOldGen: 1398143K->1397961K(1398144K)] 1974911K->1447521K(2036480K) [PSPermGen: 307470K->307470K(307776K)], 1.3118380 secs] [Times: user=2.30 sys=0.00, real=1.32 secs] 
2015-04-30T11:01:18.204+0200: 15975.712: [Full GC [PSYoungGen: 576768K->25394K(638336K)] [ParOldGen: 1397965K->1397950K(1398144K)] 1974733K->1423344K(2036480K) [PSPermGen: 307470K->307467K(307776K)], 1.2144450 secs] [Times: user=2.11 sys=0.00, real=1.21 secs] 
2015-04-30T11:01:20.284+0200: 15977.793: [Full GC [PSYoungGen: 576768K->32890K(638336K)] [ParOldGen: 1398082K->1398142K(1398144K)] 1974850K->1431033K(2036480K) [PSPermGen: 307467K->307467K(307776K)], 1.1964720 secs] [Times: user=2.10 sys=0.00, real=1.20 secs] 
2015-04-30T11:01:21.485+0200: 15978.994: [Full GC [PSYoungGen: 40616K->32969K(638336K)] [ParOldGen: 1398142K->1398141K(1398144K)] 1438759K->1431111K(2036480K) [PSPermGen: 307467K->307467K(307776K)], 1.1652960 secs] [Times: user=2.03 sys=0.00, real=1.17 secs] 
2015-04-30T11:01:23.397+0200: 15980.905: [Full GC [PSYoungGen: 576768K->58824K(638336K)] [ParOldGen: 1398143K->1397943K(1398144K)] 1974911K->1456768K(2036480K) [PSPermGen: 307467K->307467K(307776K)], 1.3021250 secs] [Times: user=2.31 sys=0.00, real=1.30 secs] 
2015-04-30T11:01:24.717+0200: 15982.225: [Full GC [PSYoungGen: 68465K->53216K(638336K)] [ParOldGen: 1397943K->1398143K(1398144K)] 1466409K->1451359K(2036480K) [PSPermGen: 307467K->307467K(307776K)], 1.2082250 secs] [Times: user=2.10 sys=0.00, real=1.21 secs] 
2015-04-30T11:01:27.386+0200: 15984.894: [Full GC [PSYoungGen: 576768K->41286K(638336K)] [ParOldGen: 1398143K->1397982K(1398144K)] 1974911K->1439268K(2036480K) [PSPermGen: 307467K->307467K(307776K)], 1.2909460 secs] [Times: user=2.29 sys=0.00, real=1.29 secs] 
2015-04-30T11:01:29.271+0200: 15986.779: [Full GC [PSYoungGen: 576768K->27766K(638336K)] [ParOldGen: 1397982K->1398142K(1398144K)] 1974750K->1425908K(2036480K) [PSPermGen: 307467K->307467K(307776K)], 1.1639540 secs] [Times: user=2.03 sys=0.00, real=1.16 secs] 
2015-04-30T11:01:31.260+0200: 15988.769: [Full GC [PSYoungGen: 576768K->36699K(638336K)] [ParOldGen: 1398142K->1398084K(1398144K)] 1974910K->1434783K(2036480K) [PSPermGen: 307470K->307470K(307776K)], 1.2504410 secs] [Times: user=2.20 sys=0.00, real=1.26 secs] 
2015-04-30T11:01:33.183+0200: 15990.691: [Full GC [PSYoungGen: 576768K->25671K(638336K)] [ParOldGen: 1398084K->1398142K(1398144K)] 1974852K->1423814K(2036480K) [PSPermGen: 307470K->307470K(307776K)], 1.2439080 secs] [Times: user=2.19 sys=0.00, real=1.24 secs] 
2015-04-30T11:01:35.113+0200: 15992.622: [Full GC [PSYoungGen: 576768K->38723K(638336K)] [ParOldGen: 1398142K->1398140K(1398144K)] 1974910K->1436864K(2036480K) [PSPermGen: 307470K->307470K(307776K)], 1.2855140 secs] [Times: user=2.25 sys=0.00, real=1.28 secs] 
2015-04-30T11:01:36.975+0200: 15994.484: [Full GC [PSYoungGen: 576768K->38745K(638336K)] [ParOldGen: 1398140K->1398084K(1398144K)] 1974908K->1436829K(2036480K) [PSPermGen: 307470K->307470K(307776K)], 1.2950800 secs] [Times: user=2.28 sys=0.00, real=1.29 secs] 
2015-04-30T11:01:38.964+0200: 15996.472: [Full GC [PSYoungGen: 576768K->33921K(638336K)] [ParOldGen: 1398084K->1398143K(1398144K)] 1974852K->1432065K(2036480K) [PSPermGen: 307470K->307470K(307776K)], 1.2367630 secs] [Times: user=2.17 sys=0.00, real=1.23 secs] 
2015-04-30T11:01:40.830+0200: 15998.338: [Full GC [PSYoungGen: 576768K->33497K(638336K)] [ParOldGen: 1398143K->1398141K(1398144K)] 1974911K->1431638K(2036480K) [PSPermGen: 307503K->307503K(307840K)], 1.2936280 secs] [Times: user=2.25 sys=0.00, real=1.30 secs] 
2015-04-30T11:01:42.832+0200: 16000.341: [Full GC [PSYoungGen: 576768K->38106K(638336K)] [ParOldGen: 1398141K->1398131K(1398144K)] 1974909K->1436237K(2036480K) [PSPermGen: 307508K->307508K(307840K)], 1.3531370 secs] [Times: user=2.34 sys=0.00, real=1.35 secs] 
2015-04-30T11:01:44.846+0200: 16002.354: [Full GC [PSYoungGen: 576768K->29489K(638336K)] [ParOldGen: 1398131K->1398140K(1398144K)] 1974899K->1427630K(2036480K) [PSPermGen: 307508K->307508K(307840K)], 1.1770150 secs] [Times: user=2.06 sys=0.00, real=1.18 secs] 
2015-04-30T11:01:46.800+0200: 16004.308: [Full GC [PSYoungGen: 576768K->36730K(638336K)] [ParOldGen: 1398140K->1398143K(1398144K)] 1974908K->1434874K(2036480K) [PSPermGen: 307508K->307508K(307840K)], 1.2761790 secs] [Times: user=2.26 sys=0.00, real=1.28 secs] 
2015-04-30T11:01:48.919+0200: 16006.428: [Full GC [PSYoungGen: 576768K->46650K(638336K)] [ParOldGen: 1398143K->1397908K(1398144K)] 1974911K->1444558K(2036480K) [PSPermGen: 307508K->307508K(307840K)], 1.3290270 secs] [Times: user=2.35 sys=0.00, real=1.33 secs] 
2015-04-30T11:01:50.901+0200: 16008.409: [Full GC [PSYoungGen: 576768K->43550K(638336K)] [ParOldGen: 1397908K->1398142K(1398144K)] 1974676K->1441693K(2036480K) [PSPermGen: 307508K->307508K(307840K)], 1.2121480 secs] [Times: user=2.11 sys=0.00, real=1.21 secs] 
2015-04-30T11:01:52.792+0200: 16010.301: [Full GC [PSYoungGen: 576768K->32252K(638336K)] [ParOldGen: 1398142K->1398142K(1398144K)] 1974910K->1430394K(2036480K) [PSPermGen: 307508K->307508K(307840K)], 1.1738220 secs] [Times: user=2.06 sys=0.00, real=1.18 secs] 
2015-04-30T11:01:54.698+0200: 16012.207: [Full GC [PSYoungGen: 576768K->40351K(638336K)] [ParOldGen: 1398142K->1398122K(1398144K)] 1974910K->1438473K(2036480K) [PSPermGen: 307508K->307508K(307840K)], 1.2184120 secs] [Times: user=2.13 sys=0.00, real=1.22 secs] 
2015-04-30T11:01:56.581+0200: 16014.090: [Full GC [PSYoungGen: 576768K->51145K(638336K)] [ParOldGen: 1398122K->1397818K(1398144K)] 1974890K->1448963K(2036480K) [PSPermGen: 307508K->307508K(307776K)], 1.2204630 secs] [Times: user=2.15 sys=0.00, real=1.22 secs] 
2015-04-30T11:01:58.522+0200: 16016.030: [Full GC [PSYoungGen: 576768K->45045K(638336K)] [ParOldGen: 1397818K->1396518K(1398144K)] 1974586K->1441563K(2036480K) [PSPermGen: 307524K->307504K(307840K)], 1.3422560 secs] [Times: user=2.37 sys=0.00, real=1.34 secs] 
2015-04-30T11:02:00.559+0200: 16018.068: [GC [PSYoungGen: 576768K->59954K(636736K)] 1973802K->1456988K(2034880K), 0.2391820 secs] [Times: user=0.47 sys=0.00, real=0.24 secs] 
2015-04-30T11:02:01.545+0200: 16019.054: [Full GC [PSYoungGen: 636722K->44520K(636736K)] [ParOldGen: 1397748K->1398143K(1398144K)] 2034470K->1442663K(2034880K) [PSPermGen: 307508K->307508K(307840K)], 1.3049690 secs] [Times: user=2.29 sys=0.01, real=1.30 secs] 
2015-04-30T11:02:03.785+0200: 16021.293: [Full GC [PSYoungGen: 576768K->46249K(636736K)] [ParOldGen: 1398143K->1398141K(1398144K)] 1974911K->1444390K(2034880K) [PSPermGen: 307508K->307508K(307840K)], 1.2749070 secs] [Times: user=2.25 sys=0.00, real=1.28 secs] 
2015-04-30T11:02:05.665+0200: 16023.174: [Full GC [PSYoungGen: 576768K->47378K(636736K)] [ParOldGen: 1398143K->1398143K(1398144K)] 1974911K->1445522K(2034880K) [PSPermGen: 307523K->307523K(307840K)], 1.2608770 secs] [Times: user=2.21 sys=0.00, real=1.27 secs] 
2015-04-30T11:02:07.660+0200: 16025.169: [Full GC [PSYoungGen: 576768K->34799K(636736K)] [ParOldGen: 1398143K->1398141K(1398144K)] 1974911K->1432940K(2034880K) [PSPermGen: 307566K->307566K(307904K)], 1.3548270 secs] [Times: user=2.37 sys=0.00, real=1.35 secs] 
2015-04-30T11:02:09.740+0200: 16027.249: [Full GC [PSYoungGen: 576768K->47591K(636736K)] [ParOldGen: 1398141K->1398140K(1398144K)] 1974909K->1445731K(2034880K) [PSPermGen: 307566K->307566K(307904K)], 1.3396300 secs] [Times: user=2.35 sys=0.00, real=1.34 secs] 

```

Any hint about any possibie causes ?

Our application is build upon:
- Java 1.7
- Spring 3.2.8
- Spring WebFlow 2.3.2 
- Spring Integration 3.0.2
- JBOSS EAP6

ps : sorry for my bad english :)