Assert.isNotNull(newName, RefactoringCoreMessages.getString("RenameFieldRefactoring.assert.new_name"));
Assert.isNotNull(newName, "new name");
	public RefactoringStatus checkNewName(String newName) throws JavaModelException {		Assert.isNotNull(newName, RefactoringCoreMessages.getString("RenameFieldRefactoring.assert.new_name")); //$NON-NLS-1$		RefactoringStatus result= Checks.checkFieldName(newName);				if (isInstaceField(fField) && (! Checks.startsWithLowerCase(newName)))			result.addWarning(RefactoringCoreMessages.getString("RenameFieldRefactoring.should_start_lowercase")); //$NON-NLS-1$					if (Checks.isAlreadyNamed(fField, newName))			result.addFatalError(RefactoringCoreMessages.getString("RenameFieldRefactoring.another_name")); //$NON-NLS-1$		if (fField.getDeclaringType().getField(newName).exists())			result.addFatalError(RefactoringCoreMessages.getString("RenameFieldRefactoring.field_already_defined")); //$NON-NLS-1$		return result;	}