[BOOKKEEPER-568] NPE during GC with HierarchicalLedgerManager

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.2.0
• Fix Version/s: 4.2.1, 4.3.0
• Component/s: bookkeeper-server
• Assignee: Matteo Merli
• Reporter: Matteo Merli
• Created: 11/Feb/13 22:33
• Updated: 15/Feb/13 05:15
• Resolved: 15/Feb/13 04:32

Description

2013-02-11 14:06:28,904 - WARN  - [GarbageCollectorThread:ScanAndCompareGarbageCollector@103] - Exception when iterating over the metadata {}
java.io.IOException: Error when check more elements
	at org.apache.bookkeeper.meta.HierarchicalLedgerManager$HierarchicalLedgerRangeIterator.hasNext(HierarchicalLedgerManager.java:423)
	at org.apache.bookkeeper.bookie.ScanAndCompareGarbageCollector.gc(ScanAndCompareGarbageCollector.java:75)
	at org.apache.bookkeeper.bookie.GarbageCollectorThread.doGcLedgers(GarbageCollectorThread.java:302)
	at org.apache.bookkeeper.bookie.GarbageCollectorThread.run(GarbageCollectorThread.java:271)
Caused by: java.lang.NullPointerException
	at org.apache.bookkeeper.meta.HierarchicalLedgerManager$HierarchicalLedgerRangeIterator.hasNext(HierarchicalLedgerManager.java:419)
	... 3 more

In the code below, l2NodesIter appears to be null.

public boolean hasNext() throws IOException {
   try {
      if (l1NodesIter == null) {
          l1NodesIter = zk.getChildren(ledgerRootPath, null).iterator();
          hasMoreElement = nextL1Node();
      } else if (!l2NodesIter.hasNext()) {
          hasMoreElement = nextL1Node();
      }
   } catch (Exception e) {
      throw new IOException("Error when check more elements", e);
   }
   return hasMoreElement;
}