Eclipse shows errors but I can't find them

Solution 1:

Take a look at

Window → Show View → Problems

or

Window → Show View → Error Log

Solution 2:

Based on the error you showed ('footballforum' is missing required Java project: 'ApiDemos'), I would check your build path. Right-click the footballforum project and choose Build Path > Configure Build Path. Make sure ApiDemos is on the projects tab of the build path options.

Solution 3:

This happens from time to time in Eclipse. In the "Project" menu there's a "Clean" option, that usually takes care of the problem.

Solution 4:

Go to project>clean and select the project which display error from check box and click ok , it will clear the error for you. Click the tab which display build automatically in the project menu And if this also does not work than restart the eclipse and try again it will work.