Java version not recognized

[torjohn412]

Opening WindowBuilder editor for a WB-designed file, I get the following message:

Incompatible Java versions
"Eclipse is running under 17.01, but this Java project has a 21 Java compliance level, so WindowBuilder will not be able to load classes from this project. Use a lower level of Java for the project, or run Eclipse using a newer Java version."

Java version (in Eclipse settings): Java SE 21.0.2 -- NOT 17.01 !!
Environment description: Java SE 21
Running under MacOS on Apple silicon

What accounts for this? How can I fix this?

[ptziegler]

Eclipse is running under 17.01, but this Java project has a 21 Java compliance level

What's the value of your java.home environment variable?
In the Help menu, click About -> About Eclipse IDE -> Installation Details

Next click on the Configuration tab and filter for java.home

According to the error message, this should be Java 17.

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Alternatively, you can also change the execution environment of your WindowBuilder project to Java 17. Right-click on the project, click Properties -> Java Build Path. In the Libraries tab, select the JRE in the module path, click edit and change it to Java 17.

[torjohn412]

Thanks!

It was indeed Java 17 -- in a different folder (Applications/EclipseApp/... rather than Library/Java/..., which is where 21 was installed). I reinstalled Eclipse, and that worked.