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I am new to Java programming language and the IntelliJ IDEA 2017.1 IDE.

I just installed the IDE and I activated all the various inspections but the IDE is unable to detect the errors any time I make a mistake such as omitting a bracket or a semicolon.

This image displays the activated inspections:

Activated Inspections

This is a screenshot of my code with multiple errors but no detected by the IDE: screenshot of my code

Kindly help me solve this problem.

CrazyCoder
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Prince Lionel N'zi
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9 Answers9

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Java file is not analyzed since it's located outside of the source root. You need to either relocate the file or reconfigure your content roots so that it resides under the folder configured as the Sources root.

Sources root is marked in blue in the project view. Here is the example of the properly configured project (notice the class icon is different than on your screenshot):

java project

source root

CrazyCoder
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    Having been used to pycharm, I falsely assumed that syntax highlighting & error handling would work everywhere in IntelliJ – Kurt Jul 03 '18 at 15:45
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One more reason could be IntelliJ is running on power saver mode, this could be disabled following way:

File Menu -> Power Saver Mode

Govinda Sakhare
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This is finally what worked for me! Phew! My Problem: Whenever I exit Intellij and try to open up an old/existing project, I have trouble getting the builds and execute to work on my localhost. I'm just using localhost.

Here are the steps that finally worked on my localhost environment:

1. Go to Project Structure and Select Project

a. Set the SDK to 10 (“Java Version 10.0.2”) or whatever you are using.

b. (I think this was the main step I was missing) Set the project compiler output to point to where I want the compiled output to sit: C:\Users\kbala\OneDrive - MatrixCare\SoftWLearnings\Javamyfun\NewHelloWorld\out

c. Project Language Level: I chose “SDK Default”

2. Go to Project Structure and Select Modules

a. Click on src (this is where my source code sits).

b. Then, Click on the “Sources” folder icon on the top. This adds src to the “Source folders” on the right. You will see the color change to Blue

c. Click ok.

3. Then, click on “Add Configuration” (top right corner of Intellij)

a. Select + at the top left hand corner.

b. Select “Application”

c. Change the name to “Main”

d. Now click on the Ellipsis (three dots) in “Main Class”. You should now see your Main Class. Select it.

e. You should now see the execute arrow at that top right of Intellij. And you should see the build icon (Hammer).

This should work!

user9944315
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If you use a build system (Maven, Gradle, etc.):

Open its panel in IntelliJ, then click the reimport button. For Gradle, this button looks like a sync icon and its hovertext says "Reload All Gradle Projects".

Why it works:

Since the build system is in charge of compiling your code, it knows which files are source code. It would be a waste of computing power to look for missing semicolons in a compiled binary file, so IntelliJ won't try to find errors until it knows the file is source code.

Most build systems, Maven and Gradle included, are also dependency managers. When you write code that uses libraries or depends on a different module, IntelliJ needs to be able to understand the dependency to tell you whether your code makes sense, or whether you made a mistake like forgetting an import statement or passing the wrong type of argument into a library function. When IntelliJ doesn't understand your dependencies, it displays all your uses of imported code in red text.

Kalinda Pride
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In my case none of these solutions were solving my problem, but I knew that I had been able to get error highlights when I started working on the project so I deleted the .idea folder in the project folder, reopened IntelliJ, and got back my errors. No clue as to what could have happened

Camilo Urán
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I was getting the same issue, I just clicked on the re-import button on the maven panel and it solved the problem .

Saikat
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ankit rawat
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  • Please provide detail/elaborate answer because currently it looks like a comment, when you have 50 rep you will be able to comment. – Abhishek Gurjar Nov 07 '19 at 05:56
  • i guess - right click on pom.xml -> maven -> reload project (in modern idea) Or Maven panel in the right side, the button with 2 cycled arrows "Reload All Maven Projects" – vyacheslav.kislov Apr 08 '22 at 10:28
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I had the same issue and here it is how I solved it: Some files where ignored and I Unignored them. To do this go to Maven tab on the right panel -> right click on each project that is in grey color and click Unignore projects.

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I'll add an another reason for it. For me it was Reader mode enabled. I was not even been aware of its existence. Can be disabled in Settings -> Editor -> Reader mode.

BitLord
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In my case was a maven option! When you open the proyect in intellij, it create a notification.