Hi,

this has nothing to do with the Java version. I generally ignore this 
Eclipse-failure as I only develop in Eclipse, but run from command line. The 
reason for this behaviour is a problem with Eclipse's resource 
management/compiler with the way how some classes in Solr (especially facet 
component) are setup.

In general, it is nowadays a no-go to have so called "non-inner" pkg-private 
classes. These are classes which share the same source code file, but are not 
nested in the main class. Instead they appear next to each other in the source 
file. This is a relic from Java 1.0 and should really no longer used!

Unfortunately some Solr developers still create such non-nested classes. 
Whenever I see them I change them to be static inner classes. The problem with 
the bug caused by this is that Eclipse randomly fails (it depends on the order 
how it compiles). The problem is that Eclipse (but also other tools) cannot 
relate the non-inner class file to a source file and therefore cannot figure 
out when it needs to be recompiled.

BTW. The same problem applies to other build system like javac and Ant when it 
needs to compile. When you change such an inner non-nested inner class, it 
fails to compile in most cases unless you do "ant clean". The problem is again, 
that the compiler cannot relate the class files to source code files!

We should really fix those classes to be static and inner - or place them in 
separate source files. I am looking to find a solution to detect this with 
forbiddenapis or our Source Code Regexes, if anybody has an idea: tell me!

Uwe

-----
Uwe Schindler
Achterdiek 19, D-28357 Bremen
http://www.thetaphi.de
eMail: u...@thetaphi.de

> -----Original Message-----
> From: 380382...@qq.com [mailto:380382...@qq.com]
> Sent: Tuesday, October 17, 2017 4:43 AM
> To: java-user <java-user@lucene.apache.org>
> Subject: run in eclipse error
> 
> i am trying to run solr in eclipse. but got the error "The type
> FacetDoubleMerger is already defined". i don't know why. Whether it is jdk
> version wrong?
> Does git master need to use java9 for development?
> 
> 
> 380382...@qq.com


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