Re: Methodology to remove unused classes?

Thomas Hawtin <>
Mon, 21 Aug 2006 21:16:53 +0100
<44ea1476$0$3208$> wrote:

My team needs to get rid of classes in a large application that are no
longer used. There are around 1500 class files in total and we estimate
that about 25% of these classes are no longer used. Is there some type
of tool that can identify classes that have been run during a certain
time period or some way to identify these classes other then removing
them from a build and getting compliation errors? We are using Eclipse
as a development tool and Tomcat as a server.

If you compile with javac just specifying you entry classes, then only
reachable classes will be compiled.

If it's a simple webapp then the entry classes will be servlets,
filters, any listeners in web.xml and any you obtain through
Class.forName. I guess JSPs could potentially reference other classes.
IIRC, Jasper will save the .java files, so they can be specified too.

Once you have all of that compiled, list the class files into a text
file. Use you favourite editor (sed, say) and search and replace to
remove .class and anything from a $. Then do another search and replace
to make it into a shell/batch file to move your used source files from
one directory to another.

Tom Hawtin
Unemployed English Java programmer

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