I created a new PLAYN project based on the "Generating a skeleton project with Eclipse" instructions on the wiki
( found here: http://code.google.com/p/playn/wiki/GettingStarted#Generating_a_skeleton_project_with_Eclipse )
Everything was set up correctly but Eclipse doesn't recognize it as a java project so I lose the syntax checking, content assist, etc (I get run-time error dialog box when content assist tries to help) for java.
I get "compilation unit is not on the build path of a java project" followed by "The 'org.eclipse.mylyn.java.ui.javaAllCompletionProposalComputer' proposal computer from the 'org.eclipse.mylyn.java.ui' plug-in did not complete normally...".
Did I miss a step? Is there a way to add it to the project?
I tried editing the .project to add a java nature but that really messed up the project structure constructed by maven. (based on How do Java and Maven builders work together in eclipse?)
I tried adding a java builder to the project properties and looked adding a plug-in dependency in Maven but couldn't figure that out (I'm still learning Maven).
thanks.
Make sure you are writing code in the [project-name]-core Eclipse project rather than the [project-name] Eclipse project.
Searching around internet I found several reasons for this error. In my case the problem was that the project's nature was not Java.
To fix that:
close the project
edit file .project on project's root
Add the following line to section:
org.eclipse.jdt.core.javanature
Done. Open your project and code assist works correctly now.
Related
I don't understand exactly what is the way of working with maven projects in Eclipse.
The problems I have are often with projects I download from github. If I set the project myself it usually work, so I think I'm doing something different from the majority of people.
I'll try to detail a specific case:
I clone a repo, let's say: https://github.com/spring-guides/tut-spring-boot-oauth2
In Eclipse I import "existing maven project"
The project has a "Maven nature" as indicated by M on the folder icon
I try to run java class with main from Eclipse. First strange thins is that the "Run As" menu doesn't have "Run as a Java application"
I have to configure the configuration manually. Now it runs, but strange things happens, like I can't edit the file as the "content assist" throw errors instead of giving the normal assists.
I notice that the project has no "source folder". So my first instinct is to add a Java nature or select src as source folder
So I add Java nature to the project. This is a disaster. It can compile anymore as it can find packages. All classes have errors. I try to play around setting source folders on /src or /src/main/java. Sometimes I fix the errors but I can't run (and now I have run as Java application) but when I run it can't load the class
So in the end, I'm a bit confused and I don't know if I explained clearly what I'm doing.
I think I would like to know in a simple way how people are doing it, rather than trying to correct my steps as I'm probably creating a mess myself.
Any help or suggestion welcome.
I'm using the last version of eclipse. I don't know which other tool's versions are relevant.
P.S. I also refresh,restart,clean rebuild the project often after touching things...but it doesn't get better
Maven is a build (management) tool. Simply spoken, its task is to create a JAR that can be used as a dependency/library by other projects or when running java -jar ....
Running a project's code isn't part of it (apart from unit and integration tests code and by using non-default plugins for special situations). Running code is part of Eclipse (or any other IDE) with its Run Configurations.
I posted a similar question regarding gradle but this question is without gradle or maven.
I can not get Kotlin working properly using Eclipse IDE. This works great using IntelliJ, however many developers still use Eclipse. I have installed the Kotlin Eclipse plugin and does not work. I have downloaded the Kotlin standard library and runtime library and added them into the project. Still not working. All I get in eclipse when I have Java and Kotlin is cannot be resolve to a specified type.
I'm not using maven or gradle because I couldn't get it working with those two either.
If I mix Java and Kotlin in the same source folder I get this error.
"The type error.NonExistentClass cannot be resolved. It is indirectly referenced from required .class files"
I'm using Eclipse Neon. If anyone can help me that would be awesome, I've been trying for quite some time now and not getting anywhere. :(
Add Kotlin Nature fixes the issue. Click on your project and Configure
Kotlin -> Add Kotlin nature
This partially fixes the issue, though eclipse plugin is still buggy and auto import function still doesn't work for me.
If you're having any issue, make sure you have kotlin_bin folder added in your project. Also make sure that ALL kotlin files have the correct package name sometimes when you rename packages or move files around kotlin classes may not get updated.
Got similar issue solved by adding a new Kotlin file to a Kotlin/Java mixed project. Adding the file caused Eclipse 2018-09 (4.9.0) to add kotlin-stdlib.jar and kotlin-reflect.jar to classpath and everything started working.
Add Kotlin Nature fixes the issue. Click on your project and Configure Kotlin -> Add Kotlin nature
As of the current Eclipse version (2019-09):
You can't add Kotlin to a Java project, but you can add Java to a Kotlin project.
The procedure to accomplish a mixed Kotlin/Java project was roughly:
Install Kotlin plug-in
Create empty Kotlin project
Move the Java code into the Kotlin project
Delete the original project
Fix project references
I'm working on a project with Spring Boot and Kotlin (some controllers/mappers/classes in Java and others in Kotlin) and after trying a lot of approaches, the only that worked was to use Eclipse 03-2020 and Kotlin Plugin for Eclipse V0.8.19.
https://dl.bintray.com/jetbrains/kotlin/eclipse-plugin/0.8.19/
Before everything, close your project and uninstall the previous version of Kotlin Plugin for Eclipse.
Go to Help/Install New Software.
Copy the link of Eclipse Plugin and continue with the installation (do not forget to check all the options to install).
After the installation restart the IDE and try compile again.
If your project was like mine, it has .kt files in /src/main/kotlin, some missing references in Java. I tried compiling them but nothing worked. It turns out that my project didn't have an Eclipse Source Folder associated with the kotlin code. There were the usual ones for "src/main/java", "src/main/resources" but not one for "src/main/kotlin".
So, I created a source folder for the kotlin files.
Right click the project
New "Source Folder"
Specify folder name: "/src/main/kotlin"
This doesn't create anything in the file system but just creates a logical container for Eclipse to work with the contents. In this case, Eclipse recognized the .kt files, compiled them and all the missing references issues all cleared up.
I've created a Play Framework program via Typesafe Activator (so it follows the template exactly).
I used sbteclipse-plugin version 3.0.0 to create an Eclipse project and imported that into Scala IDE 4.0.0. These are all the latest versions at the time of writing.
The Scala IDE definitely seems to support the Play Framework. It has syntax highlighting for the custom formats, including the routing file and templates. Yet, it doesn't seem to be able to find the views from the controllers. In particular, the call to views.html.index triggers an error: "object index is not a member of package views.html".
I tried enabling refreshing using native hooks or pooling as detailed here, but it had no affect.
I should note that while the code has been compiled in the command line (with activator ~run), it hasn't been compiled in Scala IDE, since I don't know how to (it doesn't seem to be documented anywhere).
What can I do to get rid of these false errors?
EDIT: After running activator clean ~run, I have another error: The project cannot be built until build path errors are resolved. There's no further details on what these build path errors are.
Update: Just upgrade to sbteclipse version 5.1.0 and everything should work out of the box. Also make sure you follow the Play documentation on how to set up Eclipse/ScalaIDE.
This is a known bug in sbteclipse, which probably will be fixed soon.
For now, you can add the following line to your build.sbt:
EclipseKeys.createSrc := EclipseCreateSrc.All
Kill the SBT console and run sbt eclipse again. That should add the following line to the .classpath file within your project folder as a workaround:
<classpathentry kind="src" path="target/scala-2.11/twirl/main"/>
Refresh your Eclipse project to pick up the change.
I had the same issue, also with Scala IDE 4.0.0 . I followed mkurz instuctions and they worked like a charm. But instead of changing the .classpath file in the project folder manually I used Eclipse interface:
In the top menu of the main window, click on Project and then on Properties.
In the Properties window, click on Java Build Path option (options list is on the left)
In the Source tab, click on Add Folder... button.
In the Source Folder Selection window, choose the target/scala-2.11/twirl/main folder, so it is included in the compilation path. Click Ok button.
Click Ok in the Properties window.
Now the project should compile just fine :) . With that I was able to finish the play setup example in Scala IDE website
I tried #mkurz solution first, but also ran into the same error as #matt. I became frustrated that I could not generate the eclipse project without having to go to the Eclipse project properties to manually fix the build errors. After some investigation, I discovered the solution that removed all errors entirely. Add this your build.sbt:
unmanagedSourceDirectories in Compile <+= twirlCompileTemplates.target
Or if that does not work for you, you could also use:
unmanagedSourceDirectories in Compile <+= target.zipWith(scalaBinaryVersion) { (b,v) => b / s"scala-$v/twirl/main" }
Good bye, build errors!
I got the same error message.
Are you using java8 as jre in eclipse?
After switching back from java8 to java7, everything worked fine again.
If, after following Mkurz' instructions (adding EclipseKeys.CreateSrc... ), your problems are not solved, click on Project -> Properties -> Java Build Path. Look at the source folders tab.
You may find a duplicate file folder named .../src_managed/main (Thanks Matt). If so, close the project. Remove ONE of the two ../src_managed/main entries from the .classpath file (located in the base of the activator/SBT project directory). Reopen and clean the project and you should be good to go.
For me, it turned out that installed JRE in the Scala IDE was openjdk, changed it to Oracle Java 8 and it worked.
creating a parent project with only a pom.xml, and lots of sub projects such as:
my-web
my-core
my-backoffice
etc. is easy, and the sonotype eclipse plugin does most of the work.
However, getting one project to know about the source in the other project seems to be hard. E.g. when you are debugging the my-web project, and step into my-core, eclipse doesnt know where to get the source.
Looking in the Java Build Path in eclipse, the maven plugin has added my-core as a folder under "Web App Libraries". I.e. its not using the my-core-0.0.1.SNAPSHOT.jar or similar, its using the raw java files. Great!
But how to tell maven to tell eclipse to look for the source in the same place?
Im not really sure where to start. Im guessing its possible to get maven to put the source in a special jar using the maven-soure-plugin, but this will usually be out of sync with the actual java files which the web project seems to be using directly.
A quick and dirty solution is to manually Edit the Java Build Path for each project, and add my-core and other dependant projects in the "Projects" tab. Is this best practice? Any other suggestions?
A quick and dirty solution is to
manually Edit the Java Build Path for
each project, and add my-core and
other dependant projects in the
"Projects" tab.
If this doesn't happen automatically you have a configuration problem.
My Guess would be that you have a version mismatch between the pom dependencies and the actual project versions. Or your projects have an unusual name template (m2eclipse resolves projects by their artifactId AFAIK)
Either way, what always helps is in your Debug configuration (Run > Debug Configurations ...) select the Source tab and just Add... the selected projects.
Can anyone explain where the Eclipse GWT plugin defines it's entry points?
In an attempt to get my old GWT project working again with GWT 2.0, I created a default GWT 2.0 project in Eclipse and was able to run it successfully. It's the one that asks for a name and calls the 'greet' servlet on the server, which responds etc... so far so good.
I then ported all the classes from my older maven GWT project over to this new GWT project in the hopes of getting the RPC calls to work. It had many dependencies, so I also copied over the maven pom.xml, commented out all of the gwt related plugins in the pom, and managed to get the Eclipse M2Eclipse maven pluging to recognize the pom and adopt all of the maven dependencies. All of the issues in Eclipse are now resolved and it looks good to go.
However, when I click on the GWT compile icon for the project, it pops up a "GWT Compile" dialog now asking me to "Add an entry point module". There are no entry points listed to choose from in this dialog. This is frustrating because I kept the exact same GWTApp.gwt.xml and moved my code into the previously-working auto-generated GWTApp.java class.
I can't imagine why the Eclipse plugin doesn't look in the GWTApp.gwt.xml file to figure out what the entry points are.
Can anyone explain how these entry points are defined or suggest why the project stopped working?
Thanks!
I'm certain the following is the problem and solution. I've been doing GWT for about 6 years.
Whenever you import an existing maven (namely from a Mojo-generated archtype, but probably others) project into eclipse, you will get a broken configuration which will not allow you to debug until you fix it. But the fix is simple. What happens is the build path will be set to exclude all files from '[proj]/src/main/resources', and this has the effect of hiding the [proj].gwt.xml module file from eclipse. So all the GWT dialogs that look for those modules can't see them! So you can't even create a debug configuration that works.
Here's the fix:
Right-click the project, and open Properties -> Build Path dialog -> Source Tab, and look for the one ending in '.../src/main/resources', and you will see it has excluded: . So highlight just that entry and remove the '', so that it reads "Excluded: (None)". Now the dialogs (namely the debug configuration dialog), for GWT will all see your module file, and everything will work.
Just to be sure, that wouldn't be similar to this case, where the exclusion filter was a bit too large?
<classpathentry kind="src" output="target/classes" path="src/main/java"/>
<classpathentry excluding="**" kind="src" output="target/classes"
path="target/base-resources"/>
I think that you may have an exclusion filter which is too aggressive on your "target/base-resources" directory.
It seems that you have an exclusion filter of "**". Won't that match everything?
You are right! This was the problem! :)))
I didn't know what the exclusion filter was and somehow it was added automatically during the development.
Thanks for the suggestions to my question - you prompted me to find the answer. I looked and did not have any exclusion filters but checked the Java Build Path in the project properties.
When I'd added the maven dependencies, it must have implicitly changed the defined source directory of the GWT eclipse project. (Probably to src/main/java or whatever that dumb long-winded maven default path is). Eclipse offered no hints that the Java classes were not on the project build path. Once I defined the src directory explicitly for the project, the gwt.xml module appeared in the GWT Compile dialog box!
On to the next hurdle... coz it still ain't working yet! :(
Thanks for your help!
Sonatype's eclipse maven plugin is infamous for many things. One of them is excluding all the files in your resources maven folder for a given module whenever you allow it to rebuild the eclipse classpath.
m2eclipse will probably be the single reason that I re-evaluate using Intellij...
I had the same problem.
Right click the project and select properties.....
There was empty dialog (no entry points suggested).
After some digging I found that mymodule.gwt.xml file was accidentally marked as "lib" in .classpath (eclipse project file in the root of the project folder). I seems it was marked as "lib" on .classpath automatic generation (I was importing clean maven GWT project, not eclipse project).
Simply delete line with mymodule.gwt.xml from .classpath file, cause it is in src/main/resources, that is normal "src" classpath.
Right click the project and select properties. Expand and select Google -> Web Toolkit. The right pane will have a section called Entry Point Modules. Click the add button and select your .gwt.xml file.