Type org.eclipse.emf.converter.ui.contribution.base.ModelConverterPage.PageDiagnosticHandler of variable pageDiagnosticHandler does not match with type java.util.List<java.lang.Object> of variable owners
Make classes org.eclipse.emf.converter.ui.contribution.base.ModelConverterPage.PageDiagnosticHandler and java.util.List extend a common superclass
Type org.eclipse.emf.converter.ui.contribution.base.ModelConverterPage.PageDiagnosticHandler of variable pageDiagnosticHandler does not match with type java.util.List<java.lang.Object> of variable owners