We Keep Coding

"Hide" a maven artifact from the eclipse autocomplete

For reasons I don't even want to begin to get into.. I have a maven hierarchy that looks like the one below. In a nutshell, everything requires commonslang3, except one ancient artifact that requires commonslang2.
We have no issues with compile or runtime, the dependencies work as expected. The challenge we are having is at development time.
We'd like to ensure everyone on the team uses the commonslang3 APIs, but occasionally (because of the ancient artifact and Eclipse auto suggest), someone accidentally uses the commonslang2 APIs.
Normally, we would just force the desired version in our POM, but commonslang is a special snowflake. The package signature changed between comonslang2 and commonslang3, which means we would have compile failures if we excluded the older library. E.g.,
org.apache.commons.lang3.StringUtils
org.apache.commons.lang.StringUtils
My question is this, how can I configure maven/Eclipse, to use commonlang2 as needed during compile... but not populate it in the Eclipse class autosuggest list? My desired end state is that someone types 'stringuti' + ctrl + space, and the only option they see is commonslang3. I am aware that each developer can remove individual classes via (Window->Preferences->Java->Appearance->Type Filters) but that is not a viable solution for two reasons: 1) It's a large team with frequently changing resources... 2) I need an entire artifact removed, as in hundreds of classes.
Example Tree:
MyWar
-- MyModuleJar1
-- ...
-- MyModuleJar2
-- LibA
-- commonslang
-- ...
-- LibB
-- commonslang3
-- ...
-- LibC
-- commonslang3
-- ...
-- ...

In Eclipse:
Window->Preferences->Java->Appearance->Type Filters
Add org.apache.commons.lang.*
Because you want to affect auto-complete which is a function of the IDE, you are forced to change the setting in the IDE. You can export the preferences and share them of the rest of the team.

There is not much you can do about it in Eclipse other than type filters #JustinKSU mentioned.
But with Maven you can use Takari to access rules to prevent accidental inclusion of transitive dependencies. Of course this comes with a plethora of caveats with one ironically being that the Eclipse JDT compiler has to be used instead of plain javac.

Do I always have to type package name in Java?

Today I started learning Java.
I saw that package automatic gets included in .Java file.
I was wondering if it always need to be included?

Consider specify a common package for all the types within a same project.
In Java is common to start a project with a specific package setting. A package creates a namespace to disambiguate the types that it includes, to play nicelly with other projects that may or may not be in the same classpath. Normally, the package is bound to a URL of the project.
Think of Java packages like C++ namespaces.
A huge project/product written in Java can depend on lots and lots of projects, each described in a different package.
Organizations like Apache have lots of projects, organized under a common package pattern: org.apache.<<name_of_the_project>>.
Consider starting your project with a package named: com.user3552670; or something like your personal site, so persons that will consume your project can relate to the creator.

Yes and no.
It's used to specify the package of the class, read more here.
You could create a class without a package, but your code will look bad..
They exists to avoid conflicts, example between your code and default java package.
If packages doesn't exists, you can't create a class named ArrayList because already exists in Java.
Some IDEs force the fact that, if your .java file is in com/a/b/c folder his package should be com/a/b/c (If i don't remember wrong, IntellIJ IDEA do that)

Yes and no.
It must be there, but the IDE takes care of it (I don't use Netbeans, but I'd bet that it can do it, too). When moving files between packages, it has to be updated, but again, the IDE does it all.

Minimizing jar dependency sizes

an application I have written uses several third party jars. Sometimes only a small portion of the entire 50kB to 1.7mB jar is used - one or two function calls or classes.
What is the best way to reduce the jar sizes. Should I download the sources and build a jar with just the classes I need? What existing tools can help automate this (ex I briefly looked at http://code.google.com/p/jarjar/)?
Thank you
Edit 1:
I would like to lower the size of my third party 'official' jars like swingx-1.6.jar (1.4 MB), set-3.6 (1.7 MB) glazedlists-1.8.jar (820kB) , etc. so that they only contain the bare minimum classes I need
Edit 2:
Minimizing a jar by hand or by using a program like proguard is further complicated if the library uses reflection.
Injection with google guice does not work anymore after obfuscation with proguard
The answer by cletus on another post is very good How to determine which classes are used by a Java program?

Proguard would be an option. It can eliminate unused classes and methods. You can also use it to obfuscate, which can further reduce the size of your final jar. Be aware that class loading by name is liable to break unless care is taken to keep the affected classes unobfuscated.
I've found Proguard quite effective - can be a bit cryptic to understand at the outset. But I don't have any experience with similar to offer a comparison.

First of all, if you use only one class from JAR file this does not mean that this class does not use other classed from that JAR.
The option for you, if you use open source JARs, is to get sources of that JAR, attach them to your project, remove unnecessary stuff and build the changes by yourself.

You could add GenJar as an Ant task and use it to build the JAR. As it says on the library's home page,
GenJar is a specialized Ant task that
builds jar files based on class
dependencies rather than simply the
contents of a directory.
You can find it on SourceForge.

How can I generate list of classes in order of dependency?

I'm doing a build script for a Java application to run inside the Oracle JVM. In order to import the 50-odd classes, it appears I need to bring them in in order, so any dependencies are present before compilation.
For each class, I'm running 'create or replace and compile java source {className} as {classPath}' for each file. Doing this gives me a compilation error, as the required class(es) are not imported.
How can I generate a list of the classes, in dependency order - that is, as you go down the list, the class's dependencies are listed above. I would prefer to do this as an Ant task.
Also if you have a better idea of how to get these classes imported, I'd love to hear your ideas.

I can't imagine why you'd need to do this, but if you really need to do this, I wonder if hacking a little classloader that prints out each class as it loads and load your app from there would give you a dependency graph?

Compile the classes in the filesystem using the Ant task javac. Use the task depend if more rigorous dependency checking is needed. Use the loadjava tool to load the .class and .java files into the database in arbitrary order.

In order to import the 50-odd classes, it appears I need to bring them in in order so any dependencies are present before compilation.
I have never had to do such a thing simply to compile Java.
This is what Ant was born for. I'd recommend just doing this with Ant. Set the <classpath> and you'll have no trouble.

Brute force method: put the 50 CREATEs in a batch file and execute it until no errors are found. Create the loop in a shell script. Of course it will never end if there are errors in the sources, but I'm assuming they are ok.

Can you not load in a jar file? Why does it have to be individual classes?

How can I build a compile graph for Java files?

I have a large number of classes in a project, and I would like to compile all of them from a script. The thing is, the classes should be compiled in a certain order, for example: I have a class named A which depends on a class named B. Let's say class B depends on a class named C. In order for me to compile class A, I would have to compile first B and C.
Is there some tool I could use to establish the compile order of the classes, so that I don't have to parse each class and determine this myself? I would preffer that the tool can save a file with the order of the files to be compiled, so that I could parse that from my script.
Thanks !

If you compile all of them at the same time (in the same javac invocation), you do not need to do anything of the sort you are describing. javac is smart enough to compile all files you give to it at the same time, so it doesn't have any problem with out-of-order compilation.

The Java compiler (Javac) already builds up a dependency list of all the class files you need to compile. The real dependency here is between packages - not individual java files in the same package (this is automatically taken care of by the compiler).
Use a tool like Ant or Maven to specify and compile all the files in various packages and produce your final distribution.
If you are using an IDE like NetBeans, it automatically does this for you. Alternatively, if use a tool like JDepend

These kinds of DAG ordering problems are usually solved with topological sorting. See Wikipedia for a description. I don't know if there is a tool such as the one you are looking for, but implementing it yourself is should not be that difficult.