Bug 71354 [painting] IAE in StyledText.getBidiSegments upon revert
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
try {
				type= TextUtilities.getContentType(document, IJavaPartitions.JAVA_PARTITIONING, offset, true);
			} catch (BadLocationException exception) {
				
			}
			
			int index= super.getLineStartPosition(document, line, length, offset);
			if (type.equals(IJavaPartitions.JAVA_DOC) || type.equals(IJavaPartitions.JAVA_MULTI_LINE_COMMENT)) {
				if (index < length - 1 && line.charAt(index) == '*' && line.charAt(index + 1) != '/') {
					do {
						++index;
					} while (index < length && Character.isWhitespace(line.charAt(index)));
				}
			} else {
				if (index < length - 1 && line.charAt(index) == '/' && line.charAt(index + 1) == '/') {
					index++;
					do {
						++index;
					} while (index < length && Character.isWhitespace(line.charAt(index)));
				}
			}
			return index;
		}
	}
	/**
	 * Text navigation action to navigate to the next sub-word.
	 * 
	 * @since 3.0
	 */
	protected abstract class NextSubWordAction extends TextNavigationAction {