Spark SQL single quote escape problem

quote.scala

package me.invkrh.ad2vec

import org.apache.spark.sql.SQLContext
import org.apache.spark.sql.hive.HiveContext
import org.apache.spark.{SparkConf, SparkContext}

object Test extends App {

  val sc          = new SparkContext("local[2]", "test", new SparkConf)
  val hiveContext = new HiveContext(sc)
  val sqlContext  = new SQLContext(sc)

  val context = hiveContext
  //  val context = sqlContext

  import context.implicits._

  val df = Seq((Seq(1, 2), 2)).toDF("a", "b")
  df.registerTempTable("tbl")
  df.printSchema()

  // case 1
  context.sql("select cast(a as array<string>) from tbl").show()
  // HiveContext => org.apache.spark.sql.AnalysisException: cannot recognize input near 'array' '<' 'string' in primitive type specification; line 1 pos 17
  // SQLContext => OK

  // case 2
  context.sql("select 'a\\'b'").show()
  // HiveContext => OK
  // SQLContext => failure: ``union'' expected but ErrorToken(unclosed string literal) found

  // case 3
  df.selectExpr("cast(a as array<string>)").show() // OK with HiveContext and SQLContext

  // case 4
  df.selectExpr("'a\\'b'").show() // HiveContext, SQLContext => failure: end of input expected
}