How to fix ClassCastException with Spring Tool Suite-Plugin in Eclipse Photon

Question

I use as IDE Eclipse 4.8 Photon and I have installed the Spring Tool Suite 3 Plugin Version 3.9.7.RELEASE. So far everything is fine. Then I try to import a Spring Getting Started Project with File -> New -> Spring Boot -> Import Spring Getting Started Content

After that I get a ClassCastException:

The selected wizard could not be started. Plug-in "org.springframework.ide.eclipse.boot.wizard" was unable to instantiate class "org.springframework.ide.eclipse.boot.wizard.guides.GSImportWizard". ClassCastException: attempting to castbundleresource://1458.fwk2040301400:7/javax/ws/rs/client/ClientBuilder.class to bundleresource://1573.fwk2040301400/javax/ws/rs/client/ClientBuilder.class

How could I solve this problem?

Answer 1

Seems that the issue arises in combination of Eclipse 4.8 Photon, Spring Tools 3 Add-On 3.9.7.RELEASE and probably some other installed Plugins or Tools. I couldn't find out which plugins or tools exactly make for the problem. I changed to Eclipse 4.9 and Spring Tools 3 Add-On 3.9.8.RELEASE. Then the Import Spring Getting Started Content works without problems.