problems opening an editor reason does not exist
1: Right Click on the project -> Properties -> Project Facets -> Click on the Configuration Link -> Click on Apply Button -> Click on OK button. The above steps should set your project as a Java project. 2: I pressed Ctrl + Shift + H (Open Type in Hierarchy), typed in the class name, and opened it. The file opened in a new tab, and everything was navigable again. Ref: https://stackoverflow.com/questions/14207074/eclipse-open-declaration-in-java-project
