[ http://issues.apache.org/jira/browse/HADOOP-367?page=comments#action_12424652 ] Doug Cutting commented on HADOOP-367: -------------------------------------
We might as well just use setAccessible. Let's just add a static util method: public Object newInstance(Class aClass); This can can be implemented like JobConf.newInstance(). Then JobConf.newInstance() can call this, and we can replace all calls to WritableFactories.newInstance() with calls to this. If we ever become worried about abuse of this method, we can restrict its use to particular, approved packages or somesuch. This would be even less code! > Static blocks do not automatically run when a class is loaded in Java 5.0 > ------------------------------------------------------------------------- > > Key: HADOOP-367 > URL: http://issues.apache.org/jira/browse/HADOOP-367 > Project: Hadoop > Issue Type: Bug > Components: dfs > Affects Versions: 0.4.0 > Environment: Java 5.0 > Reporter: Benjamin Reed > Fix For: 0.5.0 > > Attachments: f.patch > > > There seems to be a change that happened between 1.4 and 1.5 with respect to > static initializers. I can't find this documented, but I can reproduce with a > very simple program. Basically, a static initializer is not called unless a > static member/method of the class is accessed or an instance is created. This > is actually what the JLS says, but until 1.5 the static initializers ran when > the class was loaded. Note that this behavior only occurs when running with > the 1.5 JRE AND compiling for 1.5. > For many Writables this isn't an issue, so the fallback behavior of the > WritableFactory works, but Block is package private, so loadEdits fails when > called from org.apache.hadoop.io.ArrayWritable.readFields() yielding the > following trace: > Caused by: java.lang.RuntimeException: java.lang.IllegalAccessException: > Class org.apache.hadoop.io.WritableFactories can not access a member of class > org.apache.hadoop.dfs.Block with modifiers "public" > at > org.apache.hadoop.io.WritableFactories.newInstance(WritableFactories.java:49) > at > org.apache.hadoop.io.ArrayWritable.readFields(ArrayWritable.java:81) > at org.apache.hadoop.dfs.FSDirectory.loadFSEdits(FSDirectory.java:532) > at org.apache.hadoop.dfs.FSDirectory.loadFSImage(FSDirectory.java:470) > at org.apache.hadoop.dfs.FSDirectory.<init>(FSDirectory.java:307) > at org.apache.hadoop.dfs.FSNamesystem.<init>(FSNamesystem.java:177) > at org.apache.hadoop.dfs.NameNode.<init>(NameNode.java:91) > at org.apache.hadoop.dfs.NameNode.<init>(NameNode.java:84) > at org.apache.hadoop.dfs.NameNode.main(NameNode.java:491) -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
