IntelliJ IDEA "cannot resolve symbol" and "cannot resolve method"

What are common causes for IntelliJ IDEA not being able to resolve built-in JVM types and methods? For e开发者_开发问答xample, when I mouse over String the tooltip says "Cannot resolve symbol 'String'". It's as if IntelliJ has doesn't know where the JVM is.

By the way, I am running OS X 10.6.6. Everything was working fine until I ran the system update this morning.

Most likely JDK configuration is not valid, try to remove and add the JDK again as I've described in the related question here.

First check if you have configured JDK correctly:

• Go to File->Project Structure -> SDKs
• your JDK home path should be something like this: /Library/Java/JavaVirtualMachine/jdk.1.7.0_79.jdk/Contents/Home
• Hit Apply and then OK

Secondly check if you have provided in path in Library's section

• Go to File->Project Structure -> Libraries
• Hit the + button
• Add the path to your src folder
• Hit Apply and then OK

This should fix the problem

I was facing the same problem when import projects into IntelliJ.

for in my case first, check SDK details and check you have configured JDK correctly or not.

Go to File-> Project Structure-> platform Settings-> SDKs

Check your JDK is correct or not.

Next, I Removed project from IntelliJ and delete all IntelliJ and IDE related files and folder from the project folder (.idea, .settings, .classpath, dependency-reduced-pom). Also, delete the target folder and re-import the project.

The above solution worked in my case.

For me, I had to remove the intellij internal sdk and started to use my local sdk. When I started to use the internal, the error was gone.

I tried almost everything but nothing was helping with the ibm jdk 1.8. to fix this issue. then I found an article from https://youtrack.jetbrains.com/issue/IDEA-279214/Cannot-resolve-symbol-String-when-using-IBM-JDK-180 and it worked like charm!!!

so sharing original help credit goes to @Serge Barano. incase anybody needs and not able to able to resolve the issue using previous solutions like me.

according to the article answer is:

IBM JDK has a weird layout and the jar with the String class is in bin directory for some reason:

d:\dev\ibm_sdk80\jre\bin\default\jclSC180\vm.jar

If you add it to the JDK classpath in IntelliJ IDEA, the issue should resolve:

For me, IntelliJ could autocomplete packages, but never seemed to admit there were actual classes at any level of the hierarchy. Neither re-choosing the SDK nor re-creating the project seemed to fix it.

What did fix it was to delete the per-user IDEA directory ( in my case ~/.IntelliJIdea2017.1/) which meant losing all my other customizations... But at least it made the issue go away.

First of all you should try File | Invalidate Caches and if it doesn't help, delete IDEA system directory. Then re-import the Maven project and see if it helps.

For me ,

File -> project structure -> Project Language Level (11) selection worked. Local variable syntax for lambda paramters.

In my case, cloning repo from the remote was the easiest way to solve this issue.