CompositeInputFormat: Unable to wrap custom InputFormats
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Key: HADOOP-3706
URL: https://issues.apache.org/jira/browse/HADOOP-3706
Project: Hadoop Core
Issue Type: Bug
Components: mapred
Affects Versions: 0.17.0
Reporter: Jingkei Ly
I am unable to use a custom InputFormat with the CompositeInputFormat as the
classloader that is used by Parser is unable to find my class.
To reproduce (although I've got an example program, if that's preferred?):
1) Create a custom InputFormat (I made a copy of SequenceFileInputFormat and
named it MyInputFormat)
2) Create a program using CompositeInputFormat [Set "mapred.join.expr" to
CompositeInputFormat.compose("outer", MyInputFormat.class, plist)]
3) Create jar file
4) Run job (must be via the jar - the problem cannot be reproduced in Local
mode)
Doing so causes the following exception:
{code}
Caused by: java.io.IOException
at org.apache.hadoop.mapred.join.Parser$WNode.parse(Parser.java:274)
at org.apache.hadoop.mapred.join.Parser.reduce(Parser.java:463)
at org.apache.hadoop.mapred.join.Parser.parse(Parser.java:481)
at
org.apache.hadoop.mapred.join.CompositeInputFormat.setFormat(CompositeInputFormat.java:77)
at
org.apache.hadoop.mapred.join.CompositeInputFormat.validateInput(CompositeInputFormat.java:118)
Caused by: java.lang.ClassNotFoundException:
my.custom.input.format.MyInputFormat
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:164)
at org.apache.hadoop.mapred.join.Parser$WNode.parse(Parser.java:270)
{code}
Should the line on Parser.java:271 be something like:
{code}
jobConf.getClassByName(sb.toString());
{code}
instead of:
{code}
Class.forName(sb.toString()).asSubclass(InputFormat.class)
{code}
to ensure the correct classloader is used?
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