Develop Reference

Adding External jar copy to Project

I created a project but I am using an external library for it. enter link description here
I added the library to my Beans as follows:
Right click on folder "Libraries"
Add Library
Create...
Gave it a name "gson 2.7"
Picked the class, source and javadoc files.
I went on and continued programming and then I added my code to Github. Then when I cloned it my Library was missing.
How can I fix this ? How can I make it dynamic so I dont have to worry about this anymore. In other words I need to add the library to my code and not just the reference.
Thanks a lot for the help

Just upload a copy of your library to github.

I have not used netbeans, but from what I understand it adds the jar somewhere outside of your project directory, and it simply adds the location of the jar to your classpath. When you upload and then clone the project from github, the jars are not uploaded/cloned, and the project structure metadata for your project is also lost from netbeans.
My suggestion is to learn and start using a build tool like maven. It takes up the responsibility of adding your dependency libraries everytime, given that you have an internet connection. It also adds the libs to the target directory of your project folder, so you probably will need the internet connection only once. The libs will be uploaded and cloned back from the github repo everytime.
IDEs like eclipse have inbuilt support for maven, so you don't even have to worry about executing the mvn commands. Here's a tutorial that will get you intrigued - with the IDE that you prefer.
https://platform.netbeans.org/tutorials/nbm-maven-quickstart.html

Thanks a lot for all the replies and comments.
Technically there are two approaches to my problem. For this articular example I chose to copy the external jar files to my project.
1. Copy jar files to your project.
Go to project properties
Under Libraries folder make sure to set up a libraries folder by following the steps.
Add Library at the bottom ( you can create or import; since I already had gson in Netbeans I just imported it.)
Press ok to confirm and you are done!
2. Use Maven
Go to plugings and make sure you have all Maven plugins installed, if not do so.
Create an new project and choose maven/java application
Follow the prompts
At this point you can start coding (in my case I just imported my class files from the other project)
Right click in "Dependencies folder and then "Add Dependency"
Under query type the repository you are looking for; in my case "com.google.code.gson : gson : 2.7"
Click add and you are done!
Thanks a lot to everyone for the help :)

Eclipse Java Project - Open Declaration always opens class file instead of .java

I'm posting this query after doing lots of googling and trying out different options for last few days. Is there an easy way to attach source in Eclipse? is the closest answer I found to my question.
From above post, I tried all solutions but each time Eclipse is opening .class file instead of .java file.
Eclipse Details:
Kepler Service Release 2
Build id:20140224-0627
Please let me know if this is a bug with Eclipse or if I am missing something.

If you are using Maven, try this:
Double click on your project in eclipse -> Maven -> Enable Workspace Resolution

This is most likely because Eclipse actually use the class file for declaring the item you have requested the declaration for, and not the source file you think it should be using.
The typical reason for this is if you have a jar file containing previously compiled classes on your build path before (or instead) of the project containing the source you want. This is very rarely desirable as it can take quite a while to discover that your edits do not take effect.
Examine your build path carefully and ensure it is as you want it to be.

Maven is likely supplying a Classpath Container to your project, and generating entries for the Java Build Path based on the pom.xml contents (the JRE System Library is another example of this). Its entries will not have source attachment unless the container decides it will, which is why the Installed JREs preference page offers to let you set Source Attachments. If the pom.xml has something like that, see if you can use it. If not, see if you can configure the Maven container from its context menu. Otherwise, you may simply be stuck.

I had this same problem: when I pressed F3 or tried to open Declaration (after right click) for any element, it took me to the bytecode .class file.
My solution:
I went to the project in Project Explorer:
right click on project name->Properties
Then in Porject Properties window,
Java Build Path->"Order and Export" tab
There I selected the folder with the .java files (source code), which was below the folder having the .class files -in my case "JRE System Library [java-11-openjdk-amd64]", and pressed 'Top' button on the right frame. Then the folder with source files moved to the top.
Finally, pressed "Apply and Close" button.
That solved my problem forever and ever.
The folder

I installed a plug-in which allows me to download the sources for a maven project.
I'm not by my develop machine right now, but I think it was this:
http://marketplace.eclipse.org/content/m2e-dynamic-sources-lookup#.U8gjGWIaySM
With this, you can select a project an have maven download the sources and make then available when you navigate the code in Eclipse. All without "leaving" Eclipse.

Check into your project modules the Java Build Path, look inside the Source tab and verify if you have "Allow output folders for source folders" checkbox flagged; in this case you just need to uncheck it and you will be able to see again the right source from java files.

This is related to the Call Hierarchy in Eclipse IDE.
If you are in a situation, where you're seeing duplicate methods inside the call hierarchy showing Members calling 'myMethod(...)', double-clicking on one of the listed methods may open the .class file instead of the .java file.
When this happens, the solution is to set the search scope in the call hierarchy to Project instead of Workspace.
After setting the search scope, you won't be seeing duplicate methods listed in the call hierarchy, and double-clicking on the listed methods will only open the .java files.
(Using Eclipse DevStyle Dark Theme)

Jar file too big

I created a simple project using WindowBuilder in Eclipse and my goal is to send it by email. I don't know what kind of computer the person is using, so I exported my project into a 'Runnable JAR File' and checked the option 'Extract required libraries into generated JAR'.
The problem is that the generated JAR file is 20MB in size!!! The project has only one simple window - nothing complicated or fancy.
I found that some people use ProGuard to include only what is really needed.
I would like to know if there is a way to optimize it 'manually'? Are there libraries that are automatically included when creating a WindowBuilder project, and how may I determine which libraries I can remove?
Thank you.

I've had the same Problem using WindowBuilder. My solution was to look for the imports in my .java file, e.g.: import org.eclipse.swt.SWT;
In the Project Explorer in Eclipse you can see that there are much more imports than needed. Those 'Build Paths' can be removed carefully.
Simply rightclick on a .jar import like "com.ibm.icu_52.1.0.v201404241930.jar" and click on "Build Path" and "Remove from Build Path". Unfortunately, you can't remove or delete the packages inside the .jars.
But using this method, I managed to reduce the size from 20.7MB to 3.87MB. It's something...

Like fge said, send the source. Or upload the .jar to dropbox if you require you partner to access all of the files in the .jar.
If you don't like dropbox, find some other cloud storage solutions through a google search. Github or Bitbucket could also be an alternative to dropbox.
Cheers.

Use the Eclipse plugin FatJar. FatJar shows you which libraries are getting imported and allows you to specify which .jars, libraries, etc., that you want built into your JAR.
FatJar

Your jarfile is too big due of the project template. Create a sample java project, then use windowdbuilder components. Do not create a project Swing Template, by this way eclipse is gonna import all eclipse gui toolkits.
Tried it out with my way, my application's length equals to 3Ko against 24MO with the template project

Attach the Source in Eclipse of a jar

I added a Student.jar into my Build Path in my eclipse like this-
Right click on the project->BuildPath->Configure Build
Path->Libraries->Add External Jars
There is one class named StudentTest in Student.jar file. When I was debugging my code in eclipse, I stepped into that StudentTest class in the Student.jar.
And after that eclipse shows me like this-
The JAR file S:\some_location\Student.jar has no source attachment.
You can attach the source by clicking Attach Source below
Now I am not sure how should I attach the source in my eclipse. And from where? Can anyone provide me step by step what I need to do.
Update:-
I tried unzipping the Student.jar and I got Student folder. And after that I tried pointing the source to Student folder But still I am not able to see the class properly so that I can debug it properly, it shows the same above behavior.

Use Java Source Attacher !
It does what eclipse should do - a right click context menu that says "Attach Java Source.
It automatically downloads the source for you and attaches it. I've only hit a couple libraries it doesn't know about and when that happens it lets you contribute the url back to the community so no one else will have a problem with that library.

Eclipse is showing no source found because there is no source available . Your jar only has the compiled classes.
You need to import the project from jar and add the Project as dependency .
Other option is to go to the
Go to Properties (for the Project) -> Java Build Path -> Libraries , select your jar file and click on the source , there will be option to attach the source and Javadocs.

A .jar file usually only contains the .class files, not the .java files they were compiled from. That's why eclipse is telling you it doesn't know the source code of that class.
"Attaching" the source to a JAR means telling eclipse where the source code can be found. Of course, if you don't know yourself, that feature is of little help. Of course, you could try googling for the source code (or check wherever you got the JAR file from).
That said, you don't necessarily need the source to debug.

This worked for me for Eclipse-Luna:
Right Click on the *.jar in the Referenced Libraries folder under your project, then click on Properties
Use the Java Source Attachment page to point to the Workspace location or the External location to the source code of that jar.

Go back in to where you added the jar. I believe its the libraries tab, I don't have Eclipse open but that sounds right. to the left of the jar file you added there should be an arrow pointing right, click that and 3 or 4 options expand, one of them being the source file of the library. Click on that and click edit(I think you can also double click it) then locate the file or folder on your hard disk, you probably have to click apply or okay and you're good to go, same with javadoc and i think the last one is native libraries. I don't pay much attention when I'm in there anymore if you couldn't tell. That's what you were asking, right?

I Know it is pretty late but it will be helpful for the other user, as we can do Job using three ways... as below 1)1. Atttach your source code using i.e, Right click on the project then properties --> Java build path--> attach your source in the source tab or you can remove jar file and attach the source in the libraries tab
2. Using eclipse source Analyzer In the eclipse market you can download the plugin java source analyzer which is used to attach the open source jar file's source code. we can achieve it after installing the plugin, by right click on the open source jar and select the attach source option.
3. Using Jadclipse in eclipse you can do it last not the least, you can achieve the decompile your code using this plugin. it is similar way you can download the plugin from the eclipse market place and install in your eclipse.
in jadclipse view you can see your .class file to decomplile source format note here you cannot see the comment and hidden things I think in your scenario you can use the option one and option three, I prefer option three only if i want to the source code not for the debug the code. else i ll code the option 1, as i have the source already available with.

Simply import the package of the required source class in your code from jar.
You can find jar's sub packages in
Eclipse -- YourProject --> Referenced libraries --> yourJars --> Packages --> Clases
Like-- I was troubling with the mysql connector jar issue
"the source attachment does not contain the source"
by giving the path of source folder it display this statement
The source attachment does not contain the source for the file StatementImpl.class
Then I just import the package of mysql connector jar which contain the required class:
import com.mysql.jdbc.*;
Then program is working fine.

I faced the same issue and solved using the below steps. Go to Windows->preferences->Editors->File Associations
Here click on Add
then type .class
click on OK
again click on Add
then type .classwithoughtsource
click on OK
Now you will be able to see JadClipse option under Java section in Windows->Preferences
Please provide the path of jad.exe file as shown below.
Path for Decompiler-C:\Users\ahr\Documents\eclipse-jee-galileo-SR2-win32\jad.exe
Directory for temporary Files-C:\Users\ahr.net.sf.jadclipse
click on Apply
Now you should be able to see the classfiles in proper format.

It is quite possible, just go to the jar in the Build Path and choose to attach a source just like follow.

Download JDEclipse from http://java-decompiler.github.io/
Follow the installation steps
If you still didn't find the source, right click on the jar file and select "Attach Library Source" option from the project folder, as you can see below.

I am using project is not Spring or spring boot based application.
I have multiple subprojects and they are nested one within another.
The answers shown here supports on first level of subproject.
If I added another sub project for source code attachement, it is not allowing me saying folder already exists error.
Looks like eclipse is out dated IDE. I am using the latest version of Eclipse version 2015-2019.
It is killing all my time.
My intension is run the application in debug mode navigate through the sub projects which are added as external dependencies (non modifiable).

I have faced same problem and resolved it by using following scenario.
First we have to determine which jar file's source code we want along with version number. For Example "Spring Core" » "4.0.6.RELEASE"
open https://mvnrepository.com/ and search file with name "Spring Core" » "4.0.6.RELEASE".
Now Maven repository will show the the details of that jar file.
In that details there is one option "View All" just click on that.
Then we will navigate to URL "https://repo1.maven.org/maven2/org/springframework/spring-core/4.0.6.RELEASE/".
there so many options so select and download "spring-core-4.0.6.RELEASE-sources.jar" in our our system and attach same jar file as a source attachment in eclipse.

Try removing the breakpoints. :)

How to add libraries to an Android project?

I would like to use Apache Commons Lang in my Android project, but I don't know how to do it. Should I use the source or the binary? How to proceed then in Eclipse?

Should I use the source or the binary?
Yes. :-)
In other words, either should be fine. Source has the advantage of allowing you to trim out stuff you don't want and fix any compatibility issues you encounter with Android. OTOH, the JAR is more convenient.
How to proceed then in Eclipse?
If you are using source, just add it to your project.
If you are using the JAR, add it to the libs/ directory of your project, then add it to your build path. Be sure to use the Add JARs button in the Build Path dialog in Eclipse to refer to the JAR that is already in your libs/ directory. Everything else will be taken care of for you.

Personally, I'd go with the binary.
Download the binary (commons-lang3-3.0-beta-bin.zip)
Extract the jar file to somewhere you are familiar with. Usually i'd have all ma java libraries in one folder (commons-lang3-3.0-beta.jar)
Right click on your project in Eclipse -> build path -> add external archives
navigate to the location you saved the extracted the jar and select it..
Viola.. Thats it..
I hope it helps.
Happy Coding..!!