java.lang.OutOfMemoryError in R12.2

Internel server error : java.lang.OutOfMemoryError
APACHE LOG:
[Mon Aug 10 10:34:18 2015] [error] [client 10.10.11.134] [ecid: 1439192058:10.133.10.150:21561400:0:1622,0] mod_oc4j:
There is no oc4j process (for destination: application://oacore) available to service request.
[Mon Aug 10 10:34:21 2015] [error] [client 10.10.10.53] [ecid: 1439191921:10.133.10.150:21692608:0:3,0] mod_oc4j:
request to OC4J BurlaAp.burla.com:21500 failed: Connect failed
[Mon Aug 10 10:34:21 2015] [error] [client 10.10.10.53] [ecid: 1439191922:10.133.10.150:21037154:0:1,0] mod_oc4j:
request to OC4J BurlaAp.burla.com:21500 failed: Connect failed
OACORE LOG(application.log):
Caused by: java.lang.OutOfMemoryError
at java.lang.Throwable.fillInStackTrace(Native Method)
at java.lang.Throwable.(Throwable.java:56)
at java.lang.Throwable.(Throwable.java:67)
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:59)
at java.lang.Integer.parseInt(Integer.java:458)
at java.lang.Integer.parseInt(Integer.java:508)
at sun.net.util.IPAddressUtil.textToNumericFormatV4(IPAddressUtil.java:88)
at java.net.InetAddress.getAllByName(InetAddress.java:1063)
at java.net.InetAddress.getAllByName(InetAddress.java:1032)
at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:114)
at oracle.net.nt.ConnOption.connect(ConnOption.java:123)
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:337)
at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:422)
at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:672)
Solution:
extend the Xmx value to something like :
server -verbose:gc –Xmx5012M -Xms256M -XX:MaxPermSize=256M -XX:NewRatio=2-XX:+PrintGC TimeStamps
in $INST_TOP/ora/10.1.3/opmn/conf/opmn.xml