How to backup a User Library in Eclipse? - java

I have 100+ jars in a project. I have manually defined the source jar location for most of them so that the javadoc becomes conveniently available within the IDE.
Now, if I have to configure the IDE on a different machine, I don't want to go through the whole process again.
Can I backup the User Library definition and import it in another instance of Eclipse?
Workarounds are welcome as long as they make javadoc available within Eclipse and don't require repeated manual work of linking source jar for each jar.

In Eclipse Select Window -> Preferences. In Preferences Dialog select Java -> Build Path -> User Libraries. In the right side list select your library and Export it.

Consider to use a tool such as Maven to manage your dependencies.

Window -> Preferences
Java -> Build Path -> User Libraries -> buttons Import and Export

Related

The class 'javax.persistence.Convert' is required to be in the selected libraries

When selecting a user library as the JPA implementation in Eclipse Dali's project settings, the following error message is displayed:
The class 'javax.persistence.Convert' is required to be in the selected libraries
But the class javax.persistence.Convert is correctly included in the classpath of my user library, so how can this problem be resolved?
This error message may arise, when the persistence jar file of the selected user library is part of your Eclipse project folder (for example in a subdirectory of the project). Eclipse Dali doesn't find the class in this case.
If you try moving this directory out of the project folder and try again, it may work.
It might be a bug.
Download Eclipse Link 2.X.Y (Version 3.x.y seems to have different libs)
From the Download use the libraries / jars
eclipselink/jlib/eclipselink.jar
eclipselink/jlib/jpa/jakarta.persistence_X.Y.Z.jar
And place them into your user Library by either
The "Manage Libraries ..." Button on the very right of your screenshot
or
Eclipse -> Windows -> Preference -> Java -> Build Path -> UserLibraries
First download eclipseLink zip file https://www.eclipse.org/downloads/download.php?file=/rt/eclipselink/releases/3.0.2/eclipselink-3.0.2.v202107120736-2a0820a817.zip
Unzip file downloaded in folder eclipse for example.
From Eclipse -> Windows -> Preference -> Java -> Build Path -> UserLibraries
Click to new -> write, eclipseLinkx.x.x Where x.x.x is the version of eclipseLink downloaded.
After, select eclipseLink and click in Add External Jars. In this step add all jars that contain of .zip eclipseLink downloaded.
Previously download library javax.persistence.Convert you can find to Google.
When download javax.persistence.Convert go back to eclipse and add library javax.persistence.Convert to eclipseLink library added.
Now, you can create projects JPA.
It seems your Eclipse doesn't have the Javax driver in it, so you have to download Javax library and add it in your project.
I had this problem and It worked for me.
download the latest version from here https://jar-download.com/artifacts/javax

I always have to rebuild my project before running it

My project won't compile itself (says all files are up to date) even if I change my code.
My only solution is to rebuild every single time.
Does it have something to do with the fact that my project files are stored on a network drive at my work?
Try copying project files on your local machine and see if it works as required; also double check preferences -> Build, Execution and Deployment -> Compiler -> Make project automatically: if I recall correctly it is disabled by default.
Go to Run/Debug Configuration by combo box of in tools bar.
Then click on your project name and in bottom of Configuration tab exist a text area with Before lunch: Make, Activate tool window. click on + button and select Make option.
This means is before any lunch your project , intellij compile aging your all classes and make resources.

How to import one Eclipse project as a library into another?

I would like to use one of my eclipse projects in another one. Is there a 'smooth' way to do that, without having to export one as a jar file and importing it into another? Especially since I work on both project simultaneously, I would like the latest changes from the imported project to be automatically built and imported into the other one. Is that possible?
It is possible. Right click on your project -> Build Path -> Configure Build Path. Switch to the Projects tab and add one. It will work as a library.
P.S. You might also want to check this: Creating a java library with Eclipse
Answer to this question explains how to import your own library in eclipse.
Quoting from the answer.
Just have "Project" reference your "Library", on windows the process
is (using menu / tab names)
Go to: Project -> Properties -> Java Build Path -> Projects
Client Add...
Select your "Library" project from the list
Click Ok
Click the other Ok Now your done and you can use import for classes in your "Library"

Eclipse: "The import java.io cannot be resolved"

I have several Android projects in Eclipse, and all is fine, except one (a library) that can not resolve any imports.
The java.io imports do resolve fine in other Android projects in the same workspace, and previously (I haven't used it for over a year) this library worked fine, too.
Any ideas?
Check two things
Eclipse preferences
Check your Eclipse preferences: Java -> Installed JREs
The one that you're using should be marked and it should be a JDK not just a JRE.
Project build path
Also check your project's build path: Right click on the project -> Properties -> Java Build Path
Check in the libraries folder whether the JRE System Library is present and ...
If not add it using Add library -> JRE System Library and then
select the correct one (from an installed JDK).
I am using Maven an this is what I did to re-solve -->
Right click on project
Maven -> Update Project. Make sure you choose 'Force update of Snapshots/Releases'.
Also check the 'clean project', 'update project conf from pom' and 'refresh workspace resource options' and click ok.
The following worked for me:
Close the project and reopen it.
OR
Clean the project ( = rebuilds the buildpath and thereby reconfigures the JDK libraries).
I was missing the JRE Systems Library in my Project Tree.
And navigating to Projects' Build Path and 'Add(ing) Library' worked!
I just ran into this problem with Eclipse 2022-6 and java-17-openjdk-amd64. I just appeared during editing in another file, the same code had worked before.
For me, all settings were correct and none of the above tricks worked. What I then did was completely removing the import command import java.io.Closeable;, saving the file, adding the same import command back at the same place, and saving again. The error disappeared.

Java API in eclipse

Im new to eclipse , can anybody tell me how to use an JAVA API in eclipse. or share any sample Java API.
Yes, how to use JavaDoc file in eclipse.
Yes, how to use JavaDoc file in eclipse.
You can download the Javadoc jar file from the respective project and include it in your build path
Eclipse==> project-->properties-->Java Build Path-->click on the jar file--> edit JavaDoc
Point it to the API URL location/Downloaded Jar file,
Typically, shift + F2 opens the API when the class is focussed upon
Do you mean: how to use a third-party Java library in your Java project in Eclipse?
Right-click your project in the Package Explorer and choose Properties. Go to "Java Build Path". Click "Add JARs" or "Add External JARs" to add the JAR file(s) of the library to your project.
"Add JARs" is for adding JAR files that are in your project directory. "Add External JARs" is for adding JAR files that are not in your project.
Note that the Eclipse help (Help / Help Contents) contains a lot of information, including information on how to work with Java projects in Eclipse and how to add libraries to your Java project.
Here are some nice Eclipse video tutorials . The version of Eclipse is dated ( 3.1 ), but the concepts are still there.
I'm not clear exactly what you're after, but if you create a new Java project, you will have access to the JRE system library's contents as a classpath container.
File->New->Java Project, enter project name, select OK.
You'll then be able to create new classes and access the Java classes.
If you want to reference another jar containing the "API", you can add it to the project's build path.
Say the jar is in the "lib" folder of your project, open the project properties (alt+enter), the Select Java Build Path, then the Libraries tab, select Add JARs..., then browse to the lib folder and select the jar you want to add and select OK.
To attach sources and javadoc to the jar, you can expand the selector in the Libraries tab, click on Source attachment and Edit... and browse to the location of the sources jar/zip, repeat for the Javadoc. The screenshot below shows you the Source attachment option for rt.jar
(source: vogella.de)
and ok back to the workbench.
You should now see that the jar is included on the project's path (the jar has a little overlaid icon on it).
If this is not what you're after, can you rephrase the question?
what you need to do is to hover mouse over some in-built method or class that are using in your program. Hold ctrl on your keyboard and click. Then eclipse asks you to attach source. click on 'attach source', browse for src.zip file after choosing 'EXTRENAL' file. or instead give path for extracted src folder under same ie external file attachment. Next time you hover over an in-built class or method it shows a small description. To view entire javadoc for same, keep holding ctrl and click on it. It worked for me.

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