Methodology to remove unused classes?

[wgblackmon]

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.

 

[Jeffrey Schwab]

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.

Could you check the access times of the class files?

ls -Rt
(or) dir /s /od

 

[Thomas Hawtin]

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

 

[Thomas Weidenfeller]

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.

What is it what you want to remove? You say "class files", this
typically means compiled java source code in files ending with .class,
or do you eman source code (.java files)?

If it is the first, remove them all and recompile. If it is the second,
also remove all .class files, compile your main class, let the java
compiler find the dependencies, check which .class files it had
generated and take the corresponding .java files for a start. You might
need some more files, depending on how your application loads classes.

Oh, and improve your configuration management procedures to avoid such
problems in the future.

/Thomas