Eclipse this compilation unit is not on the build path of a java project

Question

I can t get autocompletion to work on Eclipse    I m working on the project on svn  I set up project in Eclipse by going into   File -  Import -  Checkout As a Project -  New Project Wizard    I choose Enterprise Java Application and it s being downloaded  And everything seems to work fine except instead autocompletion working as I expect I get a popup dialog displaying the message      This compilation unit is not on the build path of a java project    I ve Googled it but everyone says that project must be Java project  But hey it is  What is the problem   Update  The catalog structure on svn looks like this   -Project name   -application      -META-INF        application xml        MANIFEST MF    build    db    deploy    dist    lib    properties    script   -src      -META-INF         someother xml  datasource info          persistence xml         folder hierarchy with source files  should be package    -web      some folders                              files                        -WEB-INF         faces-config xml         jboss-web xml         web xml      build win xml   How do I tell Eclipse where the source files folder  application xml and other configuration xml files are

User · Answer

If you re a beginner  like me   the solution may be as simple as making sure the parent folder that the file you re working in is a Java project    I made the mistake of simply creating a Java folder  then creating a file in the folder and expecting it to work  The file needs to live in a project if you want to avoid this error

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I might be picking up the wrong things from so many comments  but if you are using Maven  then are you doing the usual command prompt build and clean   Go to cmd  navigate to your workspace  usually c  workspace   Then run  mvn clean install -DskipTests   After that run  mvn eclipse eclipse eclipse clean   don t need to worry about piping    Also  do you have any module dependencies in your projects   If so  try removing the dependencies clicking apply  then readding the dependencies  As this can set eclipse right when it get s confused with buildpath sometimes   Hope this helps

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For example if there are 4 project and a root project  add the other child projects to build path of root project  If there is not selection of build path  add below codes to  project file    lt  xml version  1 0  encoding  UTF-8   gt   lt projectDescription gt       lt name gt rootProject lt  name gt       lt comment gt  lt  comment gt       lt projects gt       lt  projects gt       lt buildSpec gt           lt buildCommand gt               lt name gt org eclipse jdt core javabuilder lt  name gt               lt arguments gt               lt  arguments gt           lt  buildCommand gt           lt buildCommand gt               lt name gt org eclipse m2e core maven2Builder lt  name gt               lt arguments gt               lt  arguments gt           lt  buildCommand gt       lt  buildSpec gt       lt natures gt           lt nature gt org eclipse jdt core javanature lt  nature gt           lt nature gt org eclipse m2e core maven2Nature lt  nature gt       lt  natures gt   lt  projectDescription gt

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What worked for me was copping the  settings  directory from another project

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in my case it s a maven project  delete the project from eclipse leaving the sources close eclipse delete from filesystem   target   classpath  project  settings  open eclipse Again Import Maven Projects  This solved the problem

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This is what was missing in my  project file        lt projectDescription gt                       lt buildSpec gt               lt buildCommand gt                   lt name gt org eclipse jdt core javabuilder lt  name gt                   lt arguments gt                   lt  arguments gt               lt  buildCommand gt           lt  buildspec gt                                               lt natures gt               lt nature gt org eclipse jdt core javanature lt  nature gt               lt nature gt org eclipse m2e core maven2Nature lt  nature gt           lt  natures gt                   lt  projectDescription gt

User · Answer

I solved this by adding projects in Java Build Path Right click on the project - gt  properties - gt  java build path - gt  Add

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Your source files should be in a structure with a  package  icon in the Package Explorer view  in the menu under Window   Show View   Package Explorer or press Ctrl 3 and type pack   like this      If they are not  select the folder containing your root package  src in the image above  and select Use as Source Folder from the context menu  right click

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Here the steps for creating a source folder in eclipse    Right click on the project and go to properties Select  Java Build Path  from the properties dialog box Select the source tab and check that the source folders are correct if not click on the remove button to remove source folders  or the add button to add source folders     You can control the order in which source folders appear in a project on order and export tab on the configure build path option

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I also had this problem after converting my java project into a maven project  I solved it as follows   Right click on your project - Project Facets -  click on Java  then Apply

User · Answer

Had the same problem  but with Maven   The reason was incorrect choice of executor  my project used global settings that are not avilable from Embedded installation of Maven  Changed it to external  Window -  Preferences -  Maven -  Installations  and that fixed the problem

User · Answer

I have this issue from time-to-time and often it s because the project wasn t marked as a java project   You can change this by going to the properties for the project   Project Facets   and selecting java   You may then need to properly configure that project  but this is probably part of the problem

User · Answer

Did you have your  project file in your folders   I got the same problem  Than i realized that I didn t have the  project file

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I had same issue after importing maven project consisting of nested micro services  This is how I got it resolved in Eclipse    Right Click on Project Select Configure Select  Configure and Detect Nested Projects

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I did copy the  classpath and  project from another project and adjusted the values properly   Close the project before editing those files  when you are sure they reflect the reality  your reality anyway   re-open the project in Eclipse    The workspace is rebuilt and all should work from then on

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Delete your project  DO NOT DELETE THE ORIGIN FILE IN THE FILE SYSTEM  Right click at Package explorer area and right click import  Go to Maven folder and hit import an existing maven project    Hope it helps

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Run  mvn eclipse eclipse  from terminal

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I found that I was getting this error due to having my files  including my main class  outside of the  src folder

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You may want to try running eclipse with the -clean startup option - it tries re-building eclipse s metadata of the workspace

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Had the same problem  Solution  Context menu -  Maven -  Enable dependency management  Do not know why that was lost  when checking out

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mvn eclipse eclipse   solved my problem

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When you have a multimodules maven project under a parent project  make sure you re not editing the file in the maven parent project

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What i did is after importing the project from svn   deleted the project from workspace and imported it as a maven project from local   Then in preferences- maven- usersettings- in usersettings box gave path of settings xml which will be in apache maven folder-  conf- settings xml  and it solved the issue for me

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What I did to make one of my projects to check out properly is by  1  Import your project from svn          file-- gt import-- gt SVN-Checkout Projects From SVN   2  Find your Project and then in the  Check Out As  dialogue make sure you have the radio button selected  Check out as a project configured using the New Project Wizard   3  Go through regular steps     The wizard pulls the project properly and then setups your eclipse      without using the wizard I find that all hell breaks loose       Hope this helps

User · Answer

Like the message says  is the file somewhere on the project s Java Build Path  e g  a Source folder

[eclipse] Eclipse "this compilation unit is not on the build path of a java project"

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