When running a JUnit test, using IntelliJ IDEA, I get
How can I correct this?
- Using SDK 1.7
- Module language level is 1.7
Maven build works fine. (That's why I believe this in IDEA configuration issue)
Most likely you have incorrect compiler options imported from Maven here:
Also check project and module bytecode (target) version settings outlined on the screenshot.
Other places where the source language level is configured:
Maven default language level is 1.5 (5.0), you will see this version as the Module language level on the screenshot above.
This can be changed using maven-compiler-plugin configuration inside pom.xml
:
<project>
[...]
<build>
[...]
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
[...]
</build>
[...]
</project>
or
<project>
[...]
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
[...]
</project>
IntelliJ IDEA will respect this setting after you Reimport the Maven project in the Maven Projects tool window:
Similar to that discussed below for IntelliJ 13 & 14, but with an extra level in the Settings/Preferences panel: Settings > Build, Execution, Deployment > Compiler > Java Compiler.
In IntelliJ 13 and 14, check the Settings > Compiler > Java Compiler UI to ensure you're not targeting a different bytecode version in your module.
Have you looked at your build configuration it should like that if you use maven 3 and JDK 7
<build>
<finalName>SpringApp</finalName>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
...
</plugins>
...
</build>
If it is a Gradle project, in your build.gradle file, search for following settings:
sourceCompatibility = "xx"
targetCompatibility = "xx"
For all subrpojects, in your root build.gradle file, you may put:
subprojects { project ->
sourceCompatibility = "1.7"
targetCompatibility = "1.7"
}
Although you can manually set language levels in Idea > Settings, if it is a Gradle project, Idea automatically synchronizes module .iml files from Gradle settings ( tested with Idea 15+). So all your manual changes are overriden when gradle is refreshed.
Based on Gradle documentation, if these are not set, then current JVM configuration is used.
I found another way to run into this error. You can get this if you have been re-organizing your directory structure, and one of your poms is pointing to the old parent which no-longer configures javac (because that configuration was moved to a middle level). If this happens the top level defaults to 1.5 and the misbehaving lower level pom inherits it.
So another thing to check when you see this error is that your pom structure is matching your directory structure properly.
If Maven build works fine, try to synchronizing structure of Maven and IntelliJ IDEA projects.
In the Maven tool window, click refresh button . On pressing this button, IntelliJ IDEA parses the project structure in the Maven tool window.
Note that this might not help if you're using EAP build, since Maven synchronization feature may be broken sometimes.
If all the previous solutions haven't worked for you (which was my case), you can delete intellij config files:
Intellij will regenerate new ones later. However, BE CAREFUL, this will also delete all intellij configuration made on the projet (i.e: configuration of debug mode, ...)