[HADOOP-10011] NPE if the system can't determine its own name and you go DNS.getDefaultHost(null)

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Implemented
• Affects Version/s: 2.1.1-beta, 3.0.0-alpha1
• Fix Version/s: 2.2.0
• Release Note: Looking at the source this has been fixed: checks for null trigger {{UnknownHostException}}
• Assignee: Steve Loughran
• Reporter: Steve Loughran
• Created: 20/Jun/08 19:04
• Updated: 12/May/16 18:21
• Resolved: 11/Feb/14 00:54

Description

In a test case that I am newly writing, on my infamous "home machine with broken DNS", I cant call getByName(null) without seeing a stack trace:
Testcase: testNullInterface took 0.014 sec
Caused an ERROR
null
java.lang.NullPointerException
at java.net.NetworkInterface.getByName(NetworkInterface.java:226)
at org.apache.hadoop.net.DNS.getIPs(DNS.java:94)
at org.apache.hadoop.net.DNS.getHosts(DNS.java:141)
at org.apache.hadoop.net.DNS.getDefaultHost(DNS.java:218)
at org.apache.hadoop.net.DNS.getDefaultHost(DNS.java:235)
at org.apache.hadoop.net.TestDNS.testNullInterface(TestDNS.java:62)

Issue Links

• relates to: HADOOP-3426 Datanode does not start up if the local machines DNS isnt working right and dfs.datanode.dns.interface==default