Error when updating Maven central repository using Eclipse m2e

Question

I've been trying use Maven using Eclipse m2e since yesterday. At some point I could no longer retrieve the index list from the central repository. Updating does not seem to work, and shows the following error message:

eclipse.buildId=4.5.1.M20150904-0015
java.version=1.8.0_66
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.java.product
Command-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.java.product

org.eclipse.m2e.logback.appender
Error
Tue Jan 12 13:08:37 CET 2016
Unable to update index for central|https://repo.maven.apache.org/maven2

java.lang.NullPointerException
    at org.apache.lucene.store.IndexOutput.writeString(IndexOutput.java:102)
    at org.apache.lucene.index.SegmentInfo.write(SegmentInfo.java:504)
    at org.apache.lucene.index.SegmentInfos.write(SegmentInfos.java:307)
    at org.apache.lucene.index.SegmentInfos.prepareCommit(SegmentInfos.java:761)
    at org.apache.lucene.index.IndexWriter.startCommit(IndexWriter.java:4636)
    at org.apache.lucene.index.IndexWriter.commit(IndexWriter.java:3369)
    at org.apache.lucene.index.IndexWriter.closeInternal(IndexWriter.java:1654)
    at org.apache.lucene.index.IndexWriter.close(IndexWriter.java:1602)
    at org.apache.lucene.index.IndexWriter.close(IndexWriter.java:1578)
    at org.apache.maven.index.context.NexusIndexWriter.close(NexusIndexWriter.java:58)
    at org.apache.maven.index.context.IndexUtils.close(IndexUtils.java:376)
    at org.apache.maven.index.updater.DefaultIndexUpdater.unpackIndexData(DefaultIndexUpdater.java:529)
    at org.apache.maven.index.updater.DefaultIndexUpdater.loadIndexDirectory(DefaultIndexUpdater.java:212)
    at org.apache.maven.index.updater.DefaultIndexUpdater.access$300(DefaultIndexUpdater.java:75)
    at org.apache.maven.index.updater.DefaultIndexUpdater$LuceneIndexAdaptor.setIndexFile(DefaultIndexUpdater.java:645)
    at org.apache.maven.index.updater.DefaultIndexUpdater.fetchAndUpdateIndex(DefaultIndexUpdater.java:829)
    at org.apache.maven.index.updater.DefaultIndexUpdater.fetchAndUpdateIndex(DefaultIndexUpdater.java:156)
    at org.eclipse.m2e.core.internal.index.nexus.NexusIndexManager.updateRemoteIndex(NexusIndexManager.java:1140)
    at org.eclipse.m2e.core.internal.index.nexus.NexusIndexManager.updateIndex(NexusIndexManager.java:1084)
    at org.eclipse.m2e.core.internal.index.nexus.NexusIndexManager$1.run(NexusIndexManager.java:656)
    at org.eclipse.m2e.core.internal.index.nexus.IndexUpdaterJob.run(IndexUpdaterJob.java:72)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

I cannot expand the repository in the Maven repository view and get no search results from the repository when adding dependencies.

I've tried updating and rebuilding the index, deleting the workspace .metadata folder, the {home}/.m2 folder, the AppData/Local/Temp/ nexus/m2 entries and just re-installing Eclipse, however nothing seems to work.

Answer 1

As it turns out, my hard drive was filled up to the point that no space was left to download the 1.3 GB repository index. Freeing up the required space resolved the issue. I did remove a few GB of the deleted cache files from the Recycle Bin, so the original issue was likely caused by some other problem and resolved by deleting the Maven cache.