Bug 19075 Rename Java file to non Java file causes most actions to crash
F2 - open Java file in editor - rename it so that it has the extension .txt Almost all Java relevant actions in Edit, Source, Refactor, Naviagte and context menu are still enabled. Executing them almost always leads to some sort of exceptions.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
private final static String CODE_FORMATTER_TAB_SIZE= JavaCore.FORMATTER_TAB_SIZE;
	
	public final static String MATCHING_BRACKETS=  "matchingBrackets"; 
	
	public final static String MATCHING_BRACKETS_COLOR=  "matchingBracketsColor"; 
	
	public final static String CURRENT_LINE= "currentLine"; 
	
	public final static String CURRENT_LINE_COLOR= "currentLineColor"; 
	
	public final static String PRINT_MARGIN= "printMargin"; 
	
	public final static String PRINT_MARGIN_COLOR= "printMarginColor"; 
	
	public final static String PRINT_MARGIN_COLUMN= "printMarginColumn"; 
	
	public final static String SPACES_FOR_TABS= JavaSourceViewerConfiguration.SPACES_FOR_TABS;
	
	public final static String PROBLEM_INDICATION= "problemIndication"; 
	
	public final static String PROBLEM_INDICATION_COLOR= "problemIndicationColor"; 
	
	public final static String LINKED_POSITION_COLOR= "linkedPositionColor"; 
	
	public final static String OVERVIEW_RULER= "overviewRuler";