This problem happens intermittently for different libraries and different projects. When trying to import a library, the package will be recognized, but the class name can\'
I found the following answer from @jossef-harush and @matt-leidholm useful from another link
Integer
for example) and press ALT + ENTER (or click the light bulb icon)Setup JDK
from the intentions menuConfigure
JDK
path was incorrect (pointed on /opt/jdk1.7.0_51
instead of /opt/jdk1.7.0_65
)JDK
path