[KYLIN-3836] Kylin StringUtil.join() may cause NPE if iterator is empty

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: v2.6.1
• Assignee: Chao Long
• Reporter: Chao Long
• Created: 28/Feb/19 03:58
• Updated: 08/Mar/19 01:19
• Resolved: 04/Mar/19 10:30

Description

public static String join(Iterable<String> parts, String separator) {
    StringBuilder buf = new StringBuilder();
    Iterator<String> iterator = parts.iterator();
    if (iterator == null || (!iterator.hasNext())) {
        return null;
    }

org.apache.kylin.job.exception.ExecuteException: org.apache.kylin.job.exception.ExecuteException: java.lang.NullPointerException
at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:183)
at org.apache.kylin.job.impl.threadpool.DefaultScheduler$JobRunner.run(DefaultScheduler.java:114)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.kylin.job.exception.ExecuteException: java.lang.NullPointerException
at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:183)
at org.apache.kylin.job.execution.DefaultChainedExecutable.doWork(DefaultChainedExecutable.java:71)
at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:168)
... 4 more
Caused by: java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:191)
at com.google.common.base.Splitter.split(Splitter.java:383)
at org.apache.kylin.common.util.StringUtil.splitAndTrim(StringUtil.java:181)
at org.apache.kylin.source.hive.GarbageCollectionStep.getIntermediateTables(GarbageCollectionStep.java:95)
at org.apache.kylin.source.hive.GarbageCollectionStep.cleanUpIntermediateFlatTable(GarbageCollectionStep.java:62)
at org.apache.kylin.source.hive.GarbageCollectionStep.doWork(GarbageCollectionStep.java:48)
at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:168)
... 6 more

Issue Links

• links to: GitHub Pull Request #493