code: private ValueExpression getValueExpression(FacesContext facesContext, String expression)
     {
        String el = toELExpression(expression);
        ExpressionFactory expressionFactory = facesContext.getApplication().getExpressionFactory();
        return expressionFactory.createValueExpression(facesContext.getELContext(), el, Object.class);
     }
docs: Creates an {@link ValueExpression} for the supplied EL expression