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
PREF_STYLE_COMPACT_ASSIGNEMENT, PREF_TAB_CHAR, PREF_TAB_SIZE, PREF_SPACE_CASTEXPRESSION
		};	
	}	
	protected Control createContents(Composite parent) {
		fPixelConverter= new PixelConverter(parent);
		setShell(parent.getShell());
		
		int textWidth= fPixelConverter.convertWidthInCharsToPixels(6);
		
		int nColumns= 3;
		
		GridLayout layout= new GridLayout();
		layout.marginHeight= 0;
		layout.marginWidth= 0;
		
		Composite composite= new Composite(parent, SWT.NONE);
		composite.setLayout(layout);
		
		TabFolder folder= new TabFolder(composite, SWT.NONE);
		folder.setLayout(new TabFolderLayout());	
		folder.setLayoutData(new GridData(GridData.FILL_BOTH));
		
		String[] insertNotInsert= new String[] { INSERT, DO_NOT_INSERT };
		
		layout= new GridLayout();
		layout.numColumns= nColumns;
		
		Composite newlineComposite= new Composite(folder, SWT.NULL);
		newlineComposite.setLayout(layout);
		String label= PreferencesMessages.getString("CodeFormatterPreferencePage.newline_opening_braces.label");