Bug 40424 NPE resetting Java > Code Formatter preference page [formatter]
M2 candidate - Window - Preferences - go to the Java -> Code Formatter page - press Restore Defaults button at bottom, will get the attached exception
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/CodeFormatterConfigurationBlock.java
private static final String PREF_NEWLINE_OPENING_BRACES= JavaCore.FORMATTER_NEWLINE_OPENING_BRACE; 
	private static final String PREF_NEWLINE_CONTROL_STATEMENT= JavaCore.FORMATTER_NEWLINE_CONTROL;
	private static final String PREF_NEWLINE_CLEAR_ALL= JavaCore.FORMATTER_CLEAR_BLANK_LINES;
	private static final String PREF_NEWLINE_ELSE_IF= JavaCore.FORMATTER_NEWLINE_ELSE_IF;
	private static final String PREF_NEWLINE_EMPTY_BLOCK= JavaCore.FORMATTER_NEWLINE_EMPTY_BLOCK;
	private static final String PREF_LINE_SPLIT= JavaCore.FORMATTER_LINE_SPLIT;
	private static final String PREF_STYLE_COMPACT_ASSIGNEMENT= JavaCore.FORMATTER_COMPACT_ASSIGNMENT;
	private static final String PREF_TAB_CHAR= JavaCore.FORMATTER_TAB_CHAR;
	private static final String PREF_TAB_SIZE= JavaCore.FORMATTER_TAB_SIZE;
	private static final String PREF_SPACE_CASTEXPRESSION= JavaCore.FORMATTER_SPACE_CASTEXPRESSION;
	
	private static final String INSERT=  JavaCore.INSERT;
	private static final String DO_NOT_INSERT= JavaCore.DO_NOT_INSERT;
	
	private static final String COMPACT= JavaCore.COMPACT;
	private static final String NORMAL= JavaCore.NORMAL;