Eclipse has some pretty bizarre error messages that really don’t tell you exactly what the error is or how to fix it. This weekend I saw this one for example:
Access restriction: The type 'xyz' is not API (restriction on required library ...)
A quick Google told me what this actually means is that I have a line of code using a JDK API that is not in the currently selected runtime for the current project, but does exist in other available runtimes.
For example, when setting up a project with a Maven pom.xml, if you don’t explicitly specify what JVM version you want for the project, you get Java 5 by default.
There’s a couple of different ways to change the JVM version using Maven, but the approach I prefer is by adding properties (because it’s more concise than configuring the Maven compiler plugin):
<properties>
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.source>1.8</maven.compiler.source>
</properties>
Alternatively if you’re not using Maven, just change the JRE System Library in the project settings on the Java Build Path/Libraries tab (remove the one that’s currently there and add the version that does have the APIs that you’re using, most likely a later version).