WebSphere Commerce 7 | Solr Build Index or Server Failed to Start | java.lang.OutOfMemoryError: Java heap space | List of files generated

When you are running Solr Build Index with low memory heap or if you are not able to start the server, you might see the following error,
[10/1/17 22:14:07:840 COT] 00000117 SystemErr     R Exception in thread "Thread-54" java.lang.OutOfMemoryError: Java heap space
[10/1/17 22:14:07:841 COT] 00000117 SystemErr     R     at org.apache.lucene.index.FreqProxTermsWriterPerField$FreqProxPostingsArray.<init>(FreqProxTermsWriterPerField.java:261)
[10/1/17 22:14:07:841 COT] 00000117 SystemErr     R     at org.apache.lucene.index.FreqProxTermsWriterPerField$FreqProxPostingsArray.newInstance(FreqProxTermsWriterPerField.java:279)
[10/1/17 22:14:07:841 COT] 00000117 SystemErr     R     at org.apache.lucene.index.ParallelPostingsArray.grow(ParallelPostingsArray.java:48)
[10/1/17 22:14:07:841 COT] 00000117 SystemErr     R     at org.apache.lucene.index.TermsHashPerField$PostingsBytesStartArray.grow(TermsHashPerField.java:307)
[10/1/17 22:14:07:842 COT] 00000117 SystemErr     R     at org.apache.lucene.util.BytesRefHash.add(BytesRefHash.java:324)
[10/1/17 22:14:07:842 COT] 00000117 SystemErr     R     at org.apache.lucene.index.TermsHashPerField.add(TermsHashPerField.java:185)
[10/1/17 22:14:07:842 COT] 00000117 SystemErr     R     at org.apache.lucene.index.DocInverterPerField.processFields(DocInverterPerField.java:171)
[10/1/17 22:14:07:842 COT] 00000117 SystemErr     R     at org.apache.lucene.index.DocFieldProcessor.processDocument(DocFieldProcessor.java:248)
[10/1/17 22:14:07:842 COT] 00000117 SystemErr     R     at org.apache.lucene.index.DocumentsWriterPerThread.updateDocument(DocumentsWriterPerThread.java:253)
[10/1/17 22:14:07:843 COT] 00000117 SystemErr     R     at org.apache.lucene.index.DocumentsWriter.updateDocument(DocumentsWriter.java:453)
[10/1/17 22:14:07:843 COT] 00000117 SystemErr     R     at org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:1529)
[10/1/17 22:14:07:843 COT] 00000117 SystemErr     R     at org.apache.solr.update.DirectUpdateHandler2.addDoc0(DirectUpdateHandler2.java:236)
[10/1/17 22:14:07:843 COT] 00000117 SystemErr     R     at org.apache.solr.update.DirectUpdateHandler2.addDoc(DirectUpdateHandler2.java:160)
[10/1/17 22:14:07:844 COT] 00000117 SystemErr     R     at org.apache.solr.update.processor.RunUpdateProcessor.processAdd(RunUpdateProcessorFactory.java:69)
[10/1/17 22:14:07:844 COT] 00000117 SystemErr     R     at org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:51)
[10/1/17 22:14:07:844 COT] 00000117 SystemErr     R     at org.apache.solr.update.processor.DistributedUpdateProcessor.versionAdd(DistributedUpdateProcessor.java:729)
[10/1/17 22:14:07:844 COT] 00000117 SystemErr     R     at org.apache.solr.update.processor.DistributedUpdateProcessor.processAdd(DistributedUpdateProcessor.java:556)
[10/1/17 22:14:07:844 COT] 00000117 SystemErr     R     at org.apache.solr.update.processor.LogUpdateProcessor.processAdd(LogUpdateProcessorFactory.java:100)
[10/1/17 22:14:07:845 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.SolrWriter.upload(SolrWriter.java:70)
[10/1/17 22:14:07:845 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DataImportHandler$1.upload(DataImportHandler.java:235)
[10/1/17 22:14:07:845 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DocBuilder.buildDocument(DocBuilder.java:510)
[10/1/17 22:14:07:845 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DocBuilder.buildDocument(DocBuilder.java:414)
[10/1/17 22:14:07:845 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DocBuilder.doFullDump(DocBuilder.java:329)
[10/1/17 22:14:07:845 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DocBuilder.execute(DocBuilder.java:237)
[10/1/17 22:14:07:845 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DataImporter.doFullImport(DataImporter.java:411)
[10/1/17 22:14:07:846 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DataImporter.runCmd(DataImporter.java:483)
[10/1/17 22:14:07:846 COT] 00000117 SystemErr     R     at org.apache.solr.handler.dataimport.DataImporter$1.run(DataImporter.java:464)

If this is the case then you should be able to see the Java Heap Dumps in one of the following locations,
C:\IBM\WCDE_ENT70\bin
C:\IBM\WCDE_ENT70\logs
C:\IBM\WCDE_ENT70\wasprofile\bin
C:\IBM\WCDE_ENT70\wasprofile\logs

Java Heap Dumps will be with the following naming conversions,
 - heapdump.20171001.215526.5444.0009.phd
 - javacore.20171001.215526.5444.0010.txt
 - Snap.20171001.215526.5444.0011.trc

Please stop the server, cleanup all these heap dumps, which will be taking amount of size. After the server restart your application should be working fine.

WebSphere Commerce 7 | Storefront Catalog failed to Load | javax.el.ELException: Error reading 'subCategories' | Resolution

Sometimes, you might have merged/added/removed few files from WC Project and from that onwards,
 - Store might be coming up but, it displays none of the catalogs and throws the following exception
 - Entries in STORECAT, STOREDEFCAT might be correct as well
 - If you add catalogId in the URL as one of the parameter, it works
 - If this is the case, few Out of Box files from WC project might be missing
 - I couldn't be able to find which Out of Box WC file was missing
 - But, after replacing with Default WC project again, it started working fine

[9/25/17 16:10:47:213 COT] 0000008c LoggingHelper E /GenericJSPPageError.jsp - Error reading 'subCategories' on type com.ibm.commerce.catalog.beans.CategoryDataBean
                                 javax.el.ELException: Error reading 'subCategories' on type com.ibm.commerce.catalog.beans.CategoryDataBean
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:69)
    at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:143)
    at org.apache.el.parser.AstValue.getValue(AstValue.java:102)
    at org.apache.el.parser.AstEmpty.getValue(AstEmpty.java:29)
    at org.apache.el.parser.AstNot.getValue(AstNot.java:26)
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:263)
    at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:774)
    at com.ibm._jsp._FooterDisplayMenuCategories._jspx_meth_c_if_17(_FooterDisplayMenuCategories.java:7681)
    at com.ibm._jsp._FooterDisplayMenuCategories._jspService(_FooterDisplayMenuCategories.java:1123)
    at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:99)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1667)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1602)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:113)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:80)
    at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:908)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:507)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:181)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:259)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:732)
    at org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireString(ImportSupport.java:384)
    at org.apache.taglibs.standard.tag.common.core.ImportSupport.doEndTag(ImportSupport.java:220)
    at com.ibm._jsp._CachedHeaderDisplay._jspx_meth_c_import_5(_CachedHeaderDisplay.java:11806)
    at com.ibm._jsp._CachedHeaderDisplay._jspService(_CachedHeaderDisplay.java:1431)
    at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:99)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1667)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1602)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:113)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:80)
    at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:908)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:507)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:181)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:259)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:732)
    at org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireString(ImportSupport.java:384)
    at org.apache.taglibs.standard.tag.common.core.ImportSupport.doEndTag(ImportSupport.java:220)
    at com.ibm._jsp._GenericError._jspx_meth_c_import_2(_GenericError.java:14380)