What does the red exclamation point icon in Eclipse mean?

Question

What does the red exclamation point icon in Eclipse mean? There are lots of different search results on the Internet about "red exclamation point icons" and "red exclamation mark decorators" and "red bang icons," no doubt because lots of plugins and programming-related tools use red exclamation point icons. So, to be clear, this is the one I mean:

It appears as a decorator on projects in the Package Explorer view.

In my case, the icon went away when a missing build path variable was filled in. I'm using MyEclipse 9.0, but I don't think this is MyEclipse-specific. Other people on the Internet have reported that it has to do with other issues, including Subclipse, the .svn folder and moving files between working copies.

Solution 1

According to the documentation:

Decorates Java projects and working sets that contain build path errors

In practice, I've found that a "build path error" may be caused by any number of reasons, depending on what plugins are active. Check the "Problems" view for more information.

Solution 2

It means there is a problem with the build path in your project. If it is an android project then it mostly means the target value specified in project.properties file cannot be found. This can also be caused because of other kinds of built problems. But it is shown mostly for built problems only. See here for more details. It is about built error decorater seen in eclipse.

An extract from that page:

Build path problems are sometimes easy to miss among other problems in a project. The Package Explorer and Project Explorer views now show a new decorator on Java projects and working sets that contain build path errors:

The concrete errors can be seen in the Problems view, and if you open the view menu and select Group By > Java Problem Type, they all show up in the Build Path category:

Solution 3

I also faced a similar problem when i tried to import Source file and JAR file from one machine to another machine. The path of the JAR was different on new machine compared to old machine. I resolved it as belows

1. Right click on the "Project name"
2. Select "Build path"
3. Then select "Configure Build Path"
4. Click on "Libraries"
5. Remove all the libraries which were referring to old path

Then, the exclamation symbol on the "Project name" was removed.

Solution 4

There can be several reasons. Most of the times it may be some of the below reasons ,

1. You have deleted some of the .jar files from your /lib folder
2. You have added new .jar files
3. you have added new .jar files which may be conflict with others

So what to do is we have to resolve those missing / updating / newly_added jar files.

1. right click on the project and go to properties
2. Select Java Build Path
3. go to the Libraries tab
4. Remove the jar file references which you have removed already. There will be a red mark near them so you can identify them easily.
5. Add the references to the newly added .jar files by using Add JARs
6. Refresh the project

This will solve the problem if it's because one of the above reasons.

Solution 5

I found another scenario in which the red exclamation mark might appear. I copied a directory from one project to another. This directory included a hidden .svn directory (the original project had been committed to version control). When I checked my new project into SVN, the copied directory still contained the old SVN information, incorrectly identifying itself as an element in its original project.

I discovered the problem by looking at the Properties for the directory, selecting SVN Info, and reviewing the Resource URL. I fixed the problem by deleting the hidden .svn directory for my copied directory and refreshing my project. The red exclamation mark disappeared, and I was able to check in the directory and its contents correctly.

View more solutions

Comments

[Pops]

Since this turned out to be a standard Eclipse icon: see also stackoverflow.com/questions/1561336/…

[vsingh]

I had the errors ad remove them but I still see red icon. Kind of confusing

[IAmGroot]

This was because the uploaders build path for external Jar was different to where mine was located. +1 for info.

[iono]

"Problems" view shows nothing in the case of it being an SVN fault. Try deleting the .svn folder from the offending folder and refreshing if that happens.

[Withheld]

+1 for "Check the Problems view". In my case there was nothing wrong with the checked project but rather the project was "missing required source folder: 'target/generated/src/main/java'". That's what happens when you use Maven and you haven't built the project yet for the 1st time after checkout.

[Pops]

Thanks for your answer. I appreciate your willingness to help out, but this doesn't technically answer my question. I was wondering what the icon meant, but this just explains how to get rid of it.

[Rishi]

Also -- sometimes, it still states the JAR is linked to in the build path when you try adding a JAR back. Wait a few moments, it should fix it.

[Dayong]

It is fixed after I remove the missing source from project->properties->java build path->source.

[Josh]

Build path errors, no kidding? The "Problems" view seldom gives meaningful information. This is a terrible answer.