Bug 20446 cannot create protected or private interfaces [code manipulation]
F3 the spec allows creating protected or private nested interfaces but eclipse disallows it (the new interface wizard)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/wizards/NewTypeWizardPage.java
private ImportsStructure fImportsStructure;
		private HashSet fAddedTypes;
		 ImportsManager(ICompilationUnit createdWorkingCopy) throws CoreException {
			IPreferenceStore store= PreferenceConstants.getPreferenceStore();
			String[] prefOrder= JavaPreferencesSettings.getImportOrderPreference(store);
			int threshold= JavaPreferencesSettings.getImportNumberThreshold(store);			
			fAddedTypes= new HashSet();
			
			fImportsStructure= new ImportsStructure(createdWorkingCopy, prefOrder, threshold, true);
		}
		 ImportsStructure getImportsStructure() {
			return fImportsStructure;
		}
				
		/**
		 * Adds a new import declaration that is sorted in the existing imports.
		 * If an import already exists or the import would conflict with another import
		 * of an other type with the same simple name  the import is not added.
		 * 
		 * @param qualifiedTypeName The fully qualified name of the type to import
		 * (dot separated)
		 * @return Returns the simple type name that can be used in the code or the
		 * fully qualified type name if an import conflict prevented the import
		 */				
		public String addImport(String qualifiedTypeName) {
			fAddedTypes.add(qualifiedTypeName);