Getting “cannot find Symbol” in Java project in In

问题:

I make this call to a static singleton instance from the class "GameManager.java".

HUD.getInstance().update(timeDelta);

HUD.java contains the HUD class as well as two other related classes, HUDTextElement and HUDElement. All the classes are in the same root path ../src/org/mypackage

However, when compiling this java project in IntelliJ I get "cannot find Symbol HUD" on the line I make the HUD.getInstance() call.

This exact same code compiles just fine in eclipse, any idea what the problem is?

回答1:

Select Build->Rebuild Project will solve it

回答2:

I had the same problem, and turns out I had never completely compiled the fresh project. So right-clicking and selecting Compile'' (shift-cmd-F9 on mac) fixed it. It seems the compile on save does not 'see' non-compiled files.

Marking the src folder as source did not help in my case.

回答3:

This is likely to be your ../src folder is not marked as a "source" folder in Intellij IDEA, so it doesn't know to look there to find your class. You can right click the folder in the project explorer and choose "mark as source folder" to fix this.

回答4:

I had the same problem and fixed it by clicking File>Invalidate caches/ restart

回答5:

I was getting the same "cannot find symbol" error when I did Build -> Make Project. I fixed this by deleting my Maven /target folder, right clicking my project module and doing Maven -> Reimport, and doing Build -> Rebuild Project. This was on IntelliJ Idea 13.1.5.

It turns out the Maven -> Reimport was key, since the problem resurfaced a few times before I finally did that.

回答6:

Thanks for the help so far, turns out the fix was to compile HUD.java first (right click on the file-> Compile HUD.java). After compiling the java file the rest of the project could be compiled without any problems.

I don't really know why this fixed it, or why IntelliJ wouldn't do this automatically, but root error seems it has to do with IntelliJ not correctly handling having multiple classes in a single .java file.

回答7:

I use maven in my project. For some reason IntelliJ was giving me these kind of wierd errors. I ran mvn clean and tried a resync and these errors disappeared.

回答8:

I know this is an old question, but as per my recent experience, this happens because the build resources are either deleted or Idea cannot recognize them as the source.

Wherever the error appears, provide sources for the folder/directory and this error must be resolved.

Sometimes even when we assign sources for the whole folder, individual classes might still be unavailable. For novice users simple solution is to import a fresh copy and build the application again to be good to go.

It is advisable to do a clean install after this.

回答9:

I had to right-click the project, and select "Reimport" under the "Run Maven" submenu.

回答10:

Since this is the first hit on Google searching for "intelliJ cannot find symbol" error, I'm gonna throw in my solution as well.

The problem for me was that my project originated from Eclipse, and some files contained dependency on classes that were generated in src/generated-sources by specifications in pom.xml. For some reason, this was not properly executed when I first opened the project and rebuilding/re-importing did not help, so the files were never generated.

The solution was to right-click on the module, and select Maven -> Generate Sources and Update Folders That solved the issue and I could compile.

回答11:

Make sure the source file of the java class you are trying to refer to has a .java extension. It was .aj in my case (I must have hit "Create aspect" instead of "Create class" when creating it). IntelliJ shows the same icon for this file as for "normal" class, but compiler does not see it when building.

Changing .aj to .java fixed it in my case.

回答12:

Sometimes the class you want is in the test source directory. Happened to me, anyway…

回答13:

I was having the same problem except that I was importing the classes for which dependencies were not resolving somehow. I refreshed maven projects, Rebuild Project. It still did not resolve. Looks like IntelliJ was caching something incorrectly. I restarted IntelliJ and that resolved the dependencies. I guess it cleared the cache somehow.

回答14:

For my case, the issue was with using Lombok's experimental feature @UtilityClass in my java project in Intellij Idea, to annotate a class methods as "static". When I explicitly made each method of the class as "static" instead of using the annotation, all the compilation issues disappeared.

回答15:

recompiling the main Application.java class did it for me, right click on class > Recompile

回答16:

I know this is old, but for anyone else, make sure that the class that's missing is in the same package as the class where you get the error/where your calling it from.