Why Eclipse copies unnecessary files into the bin folder? - java

I work on a java project in Eclipse (Mars.1 Release (4.5.1)) and sometimes build an executable jar with ant. In my project folder, I have several working files and directories which are frequently used in my work but are not parts of the project (execution logs, some temp files etc). I need them to be at hand, but I don't need them in the jar. For unknown reason, Eclipse (or, may be, ant?) sometimes copies them into the bin folder, and when I build the jar they get packed into it. I can not figure out the exact moment when these files get copied into the bin folder. In order to keep the jar clean, I have to constantly keep my eyes on the bin folder and delete the unnecessary files manually. I don't like it. Why do Eclipse (or, may be, ant?) behaves this way and how can I prevent this?

Eclipse defaults to copying everything from your Source folder(s) to the output (bin) folder.
You can control this in the 'Java Build Path' page of the Project Properties.
Select the 'Source' tab and expand the 'Source folders on build path' entry. You should see 'Included (All)' and 'Excluded (None)' entries. You can edit these to control what is copied.

Related

Moving from NetBeans to eclipse, can't seem to find generated java files

I have been developing in NetBeans, I am exploring changing over to eclipse.
We have a set of directories for the modules in our project; we have scripts that check things out of Subversion and do other things with that directory tree, and we have NetBeans access the sources, etc., from that directory tree.
All our modules are built, etc., with Maven. All of this works fine from within NetBeans.
I have successfully imported all the projects into eclipse (File / Import / Maven), but evidently something is different in the handling of "generated sources". We have some castor-generated files in one module, and jaxb-generated files in another. The generated files in both cases are not found by the compiler, and therefore these modules have compile errors.
Maven is configured to generate the Java classes which cannot be found; maven clean deletes them and maven compiler:compile puts them back. But in eclipse those java files cannot be found for compiling other classes, but in NetBeans they can.
I tried deleting the generated java files, then rebuilding in eclipse; the java files were regenerated in generated-sources, but still cannot be found by the compiler when it comes time to compile (or syntax-highlight) my code.
It sort of looks like a classpath issue, but we don't set the classpath in NetBeans for a maven project. How should I configure things in eclipse so the generated class files are found?
In Eclipse in the Package Explorer right click the project folder which contains the missing files. Goto "Build Path >" then "Configure Build Path...". Properties for your project folder will open.
Click on the "Source" tab. Then click on the "Add Folder..." on the left. A source folder selector box opens, here select your folder which contains the auto generated sources. Normally it will be in the target directory. Then press ok. If this will not work, try one directory deeper or less deep.
If there is no target directory, build the project folder with maven on a shell.
The generated-sources directory will be stored in the .classpath file in your project folder.
HTH.

Eclipse & JAR Hell

EDIT: I appreciate the suggestions for Ivy or Maven, but this is just not an option for me at this time. I do not have the authority to use those tools. I am simply looking for a way to get my referenced .classpath JARs into a folder inside my project.
I have created a project that uses about 50 external JAR files that I referenced from other projects inside the same workspace.
Thus, my project's directory strucure looks like:
MyProject
src/
test/
Referenced Libraries/
... 50+ JARs
lib/
My project compiles and runs beautifully inside Eclipse. But now I need to add a buildscript so other developers can pull the project down from SVN and run it standalone. To do that, I'd like to place all the JARs that are currently in Eclipse's in-house directory Referenced Libraries and copy them into my project's lib directory which I will JAR-up with the final distribution.
I'm in Package Explorer, and have tried to just copy + paste the files from Referenced Libraries to lib/ and no dice. I get the following Eclipse error:
Cannot paste the clipboard contents into the selected elements.
Anybody have any idea how I can force this copy operation to work? If I right-click any JAR inside Referenced Libraries I see an Eclipse option called Migrate JAR file, but I'm afraid that would cut-n-paste the JARs from their current location to the new lib/ directory. This isn't feasible because there are many other projects that need these JAR files exactly where they are.
Thanks for any insight here!
Have you considered Maven? It's an exceptional tool for situations like this. For file operations it's best to use Navigator view.
I don't find another way to go but to copy yourself the jars into your lib folder, add the references to your lib files (not to external jars on your machine) and upload it to SVN.
EDIT to clarify:
Remove all references from your build path. Now you can't compile the project.
Copy every jar file you need to your project's lib folder.
Go again to build path and add the references to your jars (the ones on lib) one by one. Use the button that says "Add JARs...", not the one that says "external JARs".
Compile, and if everything is fine,
Upload the whole project to SVN.

What's in an Eclipse .classpath/.project file?

We recently had an issue with an Eclipse project for one of our team members. Tomcat was not deploying JARs of the application.
We eventually noticed the .classpath Eclipse file was not the same as for the team members where the project was OK. We replaced the .classpath file with one from a project that was OK and the Tomcat deploy was complete.
Just out of curiosity and to know at what to look in the future if something is wrong, what is inside the .classpath and .project files. What can I add in there, what does it all mean?
Eclipse is a runtime environment for plugins. Virtually everything you see in Eclipse is the result of plugins installed on Eclipse, rather than Eclipse itself.
The .project file is maintained by the core Eclipse platform, and its goal is to describe the project from a generic, plugin-independent Eclipse view. What's the project's name? what other projects in the workspace does it refer to? What are the builders that are used in order to build the project? (remember, the concept of "build" doesn't pertain specifically to Java projects, but also to other types of projects)
The .classpath file is maintained by Eclipse's JDT feature (feature = set of plugins). JDT holds multiple such "meta" files in the project (see the .settings directory inside the project); the .classpath file is just one of them. Specifically, the .classpath file contains information that the JDT feature needs in order to properly compile the project: the project's source folders (that is, what to compile); the output folders (where to compile to); and classpath entries (such as other projects in the workspace, arbitrary JAR files on the file system, and so forth).
Blindly copying such files from one machine to another may be risky. For example, if arbitrary JAR files are placed on the classpath (that is, JAR files that are located outside the workspace and are referred-to by absolute path naming), the .classpath file is rendered non-portable and must be modified in order to be portable. There are certain best practices that can be followed to guarantee .classpath file portability.
.project
When a project is created in the workspace, a project description file is automatically generated that describes the project. The sole purpose of this file is to make the project self-describing, so that a project that is zipped up or released to a server can be correctly recreated in another workspace.
.classpath
Classpath specifies which Java source files and resource files in a project are considered by the Java builder and specifies how to find types outside of the project. The Java builder compiles the Java source files into the output folder and also copies the resources into it.
Complete reference is not available for the mentioned files, as they are extensible by various plug-ins.
Basically, .project files store project-settings, such as builder and project nature settings, while .classpath files define the classpath to use during running. The classpath files contains src and target entries that correspond with folders in the project; the con entries are used to describe some kind of "virtual" entries, such as the JVM libs or in case of eclipse plug-ins dependencies (normal Java project dependencies are displayed differently, using a special src entry).
This eclipse documentation has details on the markups in .project file: The project description file
It describes the .project file as:
When a project is created in the workspace, a project description file is automatically generated that describes the project. The purpose of this file is to make the project self-describing, so that a project that is zipped up or released to a server can be correctly recreated in another workspace. This file is always called ".project"

eclipse and SVN adding jar files

I'm trying to make modifications to the trunk found at https://wafle.svn.codeplex.com/svn SVN repository location. The way that I did this in Eclipse was that I used Subclipse, added a new repository location, then opened up the project and right clicked on the trunk. Then I clicked "checkout" and checked it out as a new Java project. Then I found the folder containing the source code that I want to change and recompile and I used Build Path->Make source folder. Next, I realized that I needed 190394994 jar files that were all in different places under the project's "Third Party" folder. So I used Build Path->Configure Build Path in Eclipse, then individually added each jar I needed through "Add External Jars".
My question is; did I do all of this right, and is there something I could have done more easily, such as import all the jars at once instead of individually clicking each?
Thanks.
I'm guessing that you are embellishing a little and didn't add 190 million jar files by hand. (Even at 1 jar click per second, you would be going nonstop for 2,200 days.) Incidentally, you can shift-click and choose many jars from the same directory.
The secret is in the .classpath file; that is where the build path is stored. Someone before you has probably created a fully-orbed .classpath file and stored it in SVN.
If you created this as a new Java project, it will begin with a very simple .classpath with the folder for your project's class files and the JRE. (Apparently, SVN does not overwrite it with the .classpath or you chose not to merge your local version with the one from SVN.)
Next time, you might want to overwrite your project's .classpath with that fully-orbed one on SVN. Refresh and look at the Build Path. They should be all there and in place.
First thing: rajah9 is exactly correct - there is a .classpath file already.
You just got a little hung up on a really odd svn repo layout. the java stuff is mixed in with the .net stuff. Check out the trunk and then do a file > import... then select general > existing projects into workspace. You'll want to select the Source/JNAWindowsAuthProvider/ folder.
There is already a .classpath that references the jars in the ThirdParty folder. (not quite 190 million)
Second thing: when you added the jars as external jars, it makes an absolute path to the jar file. you want to always avoid that, if you hit the add jars button it will be a relative path.

Checking in an Eclipse project into SVN

I want to checkin a Dynamic Web Project I created in eclipse into svn. Can someone tell me which files I have to check in and which one I should not? The idea is to be able to check out the project using the New Project Wizard so that I can create the Dynamic Web Project again. More specifically here are the files/directories I have in the project --
src
WebContent
build
dist
build.xml
.project
.classpath
.settings/
The build directory is not supposed to checked in obviously. What about the other ones?
I am guessing all the . files should not be checked in either. Can some one verify this?
What is this dist directory and the .settings directory?
Also where does eclipse store the Server information (tomcat)? I don't want to check it in either.
EDIT:
I initially checked in all of the above except the build directory of course. When I checked out the project from inside Eclipse it did not prompt me to create a new project since the .project is there but Eclipse was creating a JavaEE project or something instead of the Dynamic Web Project. Did anyone else run into this behavior?
** EDIT 2 **
Found it! Turns out I should not check in the following --
.project
.settings/
.classpath
Once these 3 are removed the New project Wizard works as expected and everything is fine.
If you check in .classpath/.project/.settings you make your project Eclipse-specific. What about developers who work with Netbeans or IntelliJ? IMO it is cleaner to keep your project IDE-independent and easy to set up.
I usually go for a Maven build. The pom.xml specifies all the required dependencies and mvn eclipse:eclipse generates the .classpath/.project files for you.
The .settings directory contains local settings (like which Java version you want to use). IMO it is not useful to check this in. You can enforce Java version compliance via the Maven2 pom.
Finally, for your next project, my protip is to svn-ignore the files or directories you don't want in SVN before your first commit. In a Maven2 setup that would be .settings .classpath .project target (the default output directory of Maven2) and any other generated stuff (log files, gfembed directories, etc). In your case you would ignore build and dist instead of target.
You can svn-ignore files or directories with RIGHT_MOUSE->Team->'Add to svn:ignore' (I use the Subclipse plugin). Ignore instructions are stored as svn-properties on the parent directory. The properties on a directory can be viewed by RIGHT_MOUSE->Team->Show properties. You can also edit the properties directly there by clicking on the value field. Make sure there is an end of line after each property.
Now that you have already committed and then removed these files, ignoring is not going to work anymore in my experience. Somehow I have never managed to successfully ignore generated files which have ever been checked into the SVN repository; they are like zombies, always coming back from the dead. Maybe by deleting their entries physically in the SVN repo this can be achieved, but I've never done it.
In our case, we have checked in all you mentioned in the list except, .settings/.
With .classpath and .project checked in, users can quickly check out the project and fire up Eclipse on a new computer and just start working on it; the alternative being to configure the project manually and adding in all the jar dependencies painstakingly (if you use ant). Many open source projects do this.
Read this, there are some really good points to ponder about.
Good Question... Many of us are in a dilemma on whether we want to check in IDE related files or not. I normally go for checking in .classpath for eclipse and I use eclipse variables to make sure that team needs to just change the variable value and it works. We also check in .project so that team need not to create new project in their workspace.
I would omit the .project, .settings/, dist, and build.
The .classpath can be left in if you use variables instead of hardcoded paths. This is useful so you don't have to rebuild your classpath every time you check out the project.

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