Q:

MySql and Glassfish: Error in allocating a connection

Environment:
Windows Server 2008 R2 on Amazon EC2
Netbeans IDE with Glassfish started on it
MySql running on WAMP. 
I have created restful web services from mysql database. 
My Database tables does not have fieldnames with spaces in them. 
When I Test "RESTful Web services", the Test RESTful web services page opens and I am able to see the different entities on the right hand-side. 
When I select anyone of them and try to GET the data, 
I get HTTP Status 500 with the following error:

GET RequestFailed RequestFailed --> Status: (500) Response: { HTTP Status 500 -

type Exception report
message
descriptionThe server encountered an internal error () that prevented
  it from fulfilling this request. 
exception
javax.persistence. PersistenceException: Exception [EclipseLink-4002]
  (Eclipse Persistence Services - 2.0.1.v20100213-r6600):
  org.eclipse.persistence.exceptions. DatabaseException Internal
  Exception: java.sql. SQLException: Error in allocating a connection. 
  Cause: null Error Code: 0
note The full stack traces of the exception and its root causes are
  available in the GlassFish Server Open Source Edition 3.0.1 logs. 
  GlassFish Server Open Source Edition 3.0.1
}

Full Stack Trace from GlassFish log:
WARNING: The DatabaseSession has an external transaction controller defined by something other than the ServerPlatform.  EclipseLink will permit the override of the external transaction controller, but we recommend you consider the alternative of subclassing org.eclipse.persistence.platform.server. ServerPlatformBase and override getExternalTransactionControllerClass(). 
INFO: EclipseLink, version: Eclipse Persistence Services - 2.0.1.v20100213-r6600
WARNING: RAR5117 : Failed to obtain/create connection from connection pool [ mysql_DEPM_rootPool ].  Reason : com.sun.appserv.connectors.internal.api. PoolingException
WARNING: RAR5114 : Error allocating connection : [Error in allocating a connection.  Cause: null]
SEVERE: Local Exception Stack: 
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions. DatabaseException
Internal Exception: java.sql. SQLException: Error in allocating a connection.  Cause: null
Error Code: 0
    at org.eclipse.persistence.exceptions. DatabaseException.sqlException(DatabaseException.java:309)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:138)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:94)
    at org.eclipse.persistence.sessions. DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
    at org.eclipse.persistence.internal.sessions. DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:584)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:228)
    at org.eclipse.persistence.internal.jpa. EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:369)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:151)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:207)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:195)
    at com.sun.enterprise.container.common.impl. EntityManagerFactoryWrapper.createEntityManager(EntityManagerFactoryWrapper.java:101)
    at controller. DisciplinesJpaController.getEntityManager(DisciplinesJpaController.java:35)
    at controller. DisciplinesJpaController.findDisciplinesEntities(DisciplinesJpaController.java:127)
    at controller. DisciplinesJpaController.findDisciplinesEntities(DisciplinesJpaController.java:119)
    at service. DisciplinesRESTFacade.findAll(DisciplinesRESTFacade.java:84)
    at sun.reflect. NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect. NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect. DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect. Method.invoke(Method.java:601)
    at com.sun.jersey.server.impl.model.method.dispatch. AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:149)
    at com.sun.jersey.server.impl.model.method.dispatch. ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:67)
    at com.sun.jersey.server.impl.uri.rules. HttpMethodRule.accept(HttpMethodRule.java:259)
    at com.sun.jersey.server.impl.uri.rules. ResourceClassRule.accept(ResourceClassRule.java:83)
    at com.sun.jersey.server.impl.uri.rules. RightHandPathRule.accept(RightHandPathRule.java:133)
    at com.sun.jersey.server.impl.uri.rules. RootResourceClassesRule.accept(RootResourceClassesRule.java:71)
    at com.sun.jersey.server.impl.application. WebApplicationImpl._handleRequest(WebApplicationImpl.java:990)
    at com.sun.jersey.server.impl.application. WebApplicationImpl.handleRequest(WebApplicationImpl.java:941)
    at com.sun.jersey.server.impl.application. WebApplicationImpl.handleRequest(WebApplicationImpl.java:932)
    at com.sun.jersey.spi.container.servlet. WebComponent.service(WebComponent.java:384)
    at com.sun.jersey.spi.container.servlet. ServletContainer.service(ServletContainer.java:451)
    at com.sun.jersey.spi.container.servlet. ServletContainer.service(ServletContainer.java:632)
    at javax.servlet.http. HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core. StandardWrapper.service(StandardWrapper.java:1523)
    at org.apache.catalina.core. StandardWrapperValve.invoke(StandardWrapperValve.java:279)
    at org.apache.catalina.core. StandardContextValve.invoke(StandardContextValve.java:188)
    at org.apache.catalina.core. StandardPipeline.invoke(StandardPipeline.java:641)
    at com.sun.enterprise.web. WebPipeline.invoke(WebPipeline.java:97)
    at com.sun.enterprise.web. PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
    at org.apache.catalina.core. StandardHostValve.invoke(StandardHostValve.java:185)
    at org.apache.catalina.connector. CoyoteAdapter.doService(CoyoteAdapter.java:325)
    at org.apache.catalina.connector. CoyoteAdapter.service(CoyoteAdapter.java:226)
    at com.sun.enterprise.v3.services.impl. ContainerMapper.service(ContainerMapper.java:165)
    at com.sun.grizzly.http. ProcessorTask.invokeAdapter(ProcessorTask.java:791)
    at com.sun.grizzly.http. ProcessorTask.doProcess(ProcessorTask.java:693)
    at com.sun.grizzly.http. ProcessorTask.process(ProcessorTask.java:954)
    at com.sun.grizzly.http. DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
    at com.sun.grizzly. DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
    at com.sun.grizzly. DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
    at com.sun.grizzly. DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
    at com.sun.grizzly.http. HttpProtocolChain.execute(HttpProtocolChain.java:76)
    at com.sun.grizzly. ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
    at com.sun.grizzly. SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
    at com.sun.grizzly. ContextTask.run(ContextTask.java:69)
    at com.sun.grizzly.util. AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
    at com.sun.grizzly.util. AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
    at java.lang. Thread.run(Thread.java:722)
Caused by: java.sql. SQLException: Error in allocating a connection.  Cause: null
    at com.sun.gjc.spi.base. DataSource.getConnection(DataSource.java:112)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:126)
    ... 54 more

SEVERE: The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
javax.persistence. PersistenceException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions. DatabaseException
Internal Exception: java.sql. SQLException: Error in allocating a connection.  Cause: null
Error Code: 0
    at org.eclipse.persistence.internal.jpa. EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:397)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:151)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:207)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:195)
    at com.sun.enterprise.container.common.impl. EntityManagerFactoryWrapper.createEntityManager(EntityManagerFactoryWrapper.java:101)
    at controller. DisciplinesJpaController.getEntityManager(DisciplinesJpaController.java:35)
    at controller. DisciplinesJpaController.findDisciplinesEntities(DisciplinesJpaController.java:127)
    at controller. DisciplinesJpaController.findDisciplinesEntities(DisciplinesJpaController.java:119)
    at service. DisciplinesRESTFacade.findAll(DisciplinesRESTFacade.java:84)
    at sun.reflect. NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect. NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect. DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect. Method.invoke(Method.java:601)
    at com.sun.jersey.server.impl.model.method.dispatch. AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:149)
    at com.sun.jersey.server.impl.model.method.dispatch. ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:67)
    at com.sun.jersey.server.impl.uri.rules. HttpMethodRule.accept(HttpMethodRule.java:259)
    at com.sun.jersey.server.impl.uri.rules. ResourceClassRule.accept(ResourceClassRule.java:83)
    at com.sun.jersey.server.impl.uri.rules. RightHandPathRule.accept(RightHandPathRule.java:133)
    at com.sun.jersey.server.impl.uri.rules. RootResourceClassesRule.accept(RootResourceClassesRule.java:71)
    at com.sun.jersey.server.impl.application. WebApplicationImpl._handleRequest(WebApplicationImpl.java:990)
    at com.sun.jersey.server.impl.application. WebApplicationImpl.handleRequest(WebApplicationImpl.java:941)
    at com.sun.jersey.server.impl.application. WebApplicationImpl.handleRequest(WebApplicationImpl.java:932)
    at com.sun.jersey.spi.container.servlet. WebComponent.service(WebComponent.java:384)
    at com.sun.jersey.spi.container.servlet. ServletContainer.service(ServletContainer.java:451)
    at com.sun.jersey.spi.container.servlet. ServletContainer.service(ServletContainer.java:632)
    at javax.servlet.http. HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core. StandardWrapper.service(StandardWrapper.java:1523)
    at org.apache.catalina.core. StandardWrapperValve.invoke(StandardWrapperValve.java:279)
    at org.apache.catalina.core. StandardContextValve.invoke(StandardContextValve.java:188)
    at org.apache.catalina.core. StandardPipeline.invoke(StandardPipeline.java:641)
    at com.sun.enterprise.web. WebPipeline.invoke(WebPipeline.java:97)
    at com.sun.enterprise.web. PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
    at org.apache.catalina.core. StandardHostValve.invoke(StandardHostValve.java:185)
    at org.apache.catalina.connector. CoyoteAdapter.doService(CoyoteAdapter.java:325)
    at org.apache.catalina.connector. CoyoteAdapter.service(CoyoteAdapter.java:226)
    at com.sun.enterprise.v3.services.impl. ContainerMapper.service(ContainerMapper.java:165)
    at com.sun.grizzly.http. ProcessorTask.invokeAdapter(ProcessorTask.java:791)
    at com.sun.grizzly.http. ProcessorTask.doProcess(ProcessorTask.java:693)
    at com.sun.grizzly.http. ProcessorTask.process(ProcessorTask.java:954)
    at com.sun.grizzly.http. DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
    at com.sun.grizzly. DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
    at com.sun.grizzly. DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
    at com.sun.grizzly. DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
    at com.sun.grizzly.http. HttpProtocolChain.execute(HttpProtocolChain.java:76)
    at com.sun.grizzly. ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
    at com.sun.grizzly. SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
    at com.sun.grizzly. ContextTask.run(ContextTask.java:69)
    at com.sun.grizzly.util. AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
    at com.sun.grizzly.util. AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
    at java.lang. Thread.run(Thread.java:722)
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions. DatabaseException
Internal Exception: java.sql. SQLException: Error in allocating a connection.  Cause: null
Error Code: 0
    at org.eclipse.persistence.exceptions. DatabaseException.sqlException(DatabaseException.java:309)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:138)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:94)
    at org.eclipse.persistence.sessions. DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
    at org.eclipse.persistence.internal.sessions. DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:584)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:228)
    at org.eclipse.persistence.internal.jpa. EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:369)
    ... 49 more
Caused by: java.sql. SQLException: Error in allocating a connection.  Cause: null
    at com.sun.gjc.spi.base. DataSource.getConnection(DataSource.java:112)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:126)
    ... 54 more

WARNING: StandardWrapperValve[ServletAdaptor]: PWC1406: Servlet.service() for servlet ServletAdaptor threw exception
javax.persistence. PersistenceException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions. DatabaseException
Internal Exception: java.sql. SQLException: Error in allocating a connection.  Cause: null
Error Code: 0
    at org.eclipse.persistence.internal.jpa. EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:397)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:151)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:207)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:195)
    at com.sun.enterprise.container.common.impl. EntityManagerFactoryWrapper.createEntityManager(EntityManagerFactoryWrapper.java:101)
    at controller. DisciplinesJpaController.getEntityManager(DisciplinesJpaController.java:35)
    at controller. DisciplinesJpaController.findDisciplinesEntities(DisciplinesJpaController.java:127)
    at controller. DisciplinesJpaController.findDisciplinesEntities(DisciplinesJpaController.java:119)
    at service. DisciplinesRESTFacade.findAll(DisciplinesRESTFacade.java:84)
    at sun.reflect. NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect. NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect. DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect. Method.invoke(Method.java:601)
    at com.sun.jersey.server.impl.model.method.dispatch. AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:149)
    at com.sun.jersey.server.impl.model.method.dispatch. ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:67)
    at com.sun.jersey.server.impl.uri.rules. HttpMethodRule.accept(HttpMethodRule.java:259)
    at com.sun.jersey.server.impl.uri.rules. ResourceClassRule.accept(ResourceClassRule.java:83)
    at com.sun.jersey.server.impl.uri.rules. RightHandPathRule.accept(RightHandPathRule.java:133)
    at com.sun.jersey.server.impl.uri.rules. RootResourceClassesRule.accept(RootResourceClassesRule.java:71)
    at com.sun.jersey.server.impl.application. WebApplicationImpl._handleRequest(WebApplicationImpl.java:990)
    at com.sun.jersey.server.impl.application. WebApplicationImpl.handleRequest(WebApplicationImpl.java:941)
    at com.sun.jersey.server.impl.application. WebApplicationImpl.handleRequest(WebApplicationImpl.java:932)
    at com.sun.jersey.spi.container.servlet. WebComponent.service(WebComponent.java:384)
    at com.sun.jersey.spi.container.servlet. ServletContainer.service(ServletContainer.java:451)
    at com.sun.jersey.spi.container.servlet. ServletContainer.service(ServletContainer.java:632)
    at javax.servlet.http. HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core. StandardWrapper.service(StandardWrapper.java:1523)
    at org.apache.catalina.core. StandardWrapperValve.invoke(StandardWrapperValve.java:279)
    at org.apache.catalina.core. StandardContextValve.invoke(StandardContextValve.java:188)
    at org.apache.catalina.core. StandardPipeline.invoke(StandardPipeline.java:641)
    at com.sun.enterprise.web. WebPipeline.invoke(WebPipeline.java:97)
    at com.sun.enterprise.web. PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
    at org.apache.catalina.core. StandardHostValve.invoke(StandardHostValve.java:185)
    at org.apache.catalina.connector. CoyoteAdapter.doService(CoyoteAdapter.java:325)
    at org.apache.catalina.connector. CoyoteAdapter.service(CoyoteAdapter.java:226)
    at com.sun.enterprise.v3.services.impl. ContainerMapper.service(ContainerMapper.java:165)
    at com.sun.grizzly.http. ProcessorTask.invokeAdapter(ProcessorTask.java:791)
    at com.sun.grizzly.http. ProcessorTask.doProcess(ProcessorTask.java:693)
    at com.sun.grizzly.http. ProcessorTask.process(ProcessorTask.java:954)
    at com.sun.grizzly.http. DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
    at com.sun.grizzly. DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
    at com.sun.grizzly. DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
    at com.sun.grizzly. DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
    at com.sun.grizzly.http. HttpProtocolChain.execute(HttpProtocolChain.java:76)
    at com.sun.grizzly. ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
    at com.sun.grizzly. SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
    at com.sun.grizzly. ContextTask.run(ContextTask.java:69)
    at com.sun.grizzly.util. AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
    at com.sun.grizzly.util. AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
    at java.lang. Thread.run(Thread.java:722)
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions. DatabaseException
Internal Exception: java.sql. SQLException: Error in allocating a connection.  Cause: null
Error Code: 0
    at org.eclipse.persistence.exceptions. DatabaseException.sqlException(DatabaseException.java:309)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:138)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:94)
    at org.eclipse.persistence.sessions. DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
    at org.eclipse.persistence.internal.sessions. DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:584)
    at org.eclipse.persistence.internal.jpa. EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:228)
    at org.eclipse.persistence.internal.jpa. EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:369)
    ... 49 more
Caused by: java.sql. SQLException: Error in allocating a connection.  Cause: null
    at com.sun.gjc.spi.base. DataSource.getConnection(DataSource.java:112)
    at org.eclipse.persistence.sessions. JNDIConnector.connect(JNDIConnector.java:126)
    ... 54 more

You can try accessing a RESTful web service on the server through:
http://ec2-23-22-180-93.compute-1.amazonaws.com:13495/WebApplication2/resources/entities.disciplines
I did the same thing with the same database on another Windows 7 machine and it is working fine. 
Any help will Appreciated. 
Thanks! 

A:

I tried the same setup with another Amazon EC2 instance with higher RAM and it worked without a glitch!  Earlier, I was using an EC2 instance with 613 MB of RAM.