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.