address comments

Author: kevinyu98

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/JavaTypeInference.scala

@@ -89,7 +89,7 @@ object JavaTypeInference {
       case c: Class[_] if c == classOf[java.lang.Boolean] => (BooleanType, true)
 
       case c: Class[_] if c == classOf[java.math.BigDecimal] => (DecimalType.SYSTEM_DEFAULT, true)
-      case c: Class[_] if c == classOf[java.math.BigInteger] => (DecimalType.BIGINT_DEFAULT, true)
+      case c: Class[_] if c == classOf[java.math.BigInteger] => (DecimalType.BigIntDecimal, true)
       case c: Class[_] if c == classOf[java.sql.Date] => (DateType, true)
       case c: Class[_] if c == classOf[java.sql.Timestamp] => (TimestampType, true)
 

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala

@@ -601,14 +601,14 @@ object ScalaReflection extends ScalaReflection {
         case t if t <:< localTypeOf[java.math.BigInteger] =>
           StaticInvoke(
             Decimal.getClass,
-            DecimalType.BIGINT_DEFAULT,
+            DecimalType.BigIntDecimal,
             "apply",
             inputObject :: Nil)
 
         case t if t <:< localTypeOf[scala.math.BigInt] =>
           StaticInvoke(
             Decimal.getClass,
-            DecimalType.BIGINT_DEFAULT,
+            DecimalType.BigIntDecimal,
             "apply",
             inputObject :: Nil)
 
@@ -757,9 +757,9 @@ object ScalaReflection extends ScalaReflection {
       case t if t <:< localTypeOf[java.math.BigDecimal] =>
         Schema(DecimalType.SYSTEM_DEFAULT, nullable = true)
       case t if t <:< localTypeOf[java.math.BigInteger] =>
-        Schema(DecimalType.BIGINT_DEFAULT, nullable = true)
+        Schema(DecimalType.BigIntDecimal, nullable = true)
       case t if t <:< localTypeOf[scala.math.BigInt] =>
-        Schema(DecimalType.BIGINT_DEFAULT, nullable = true)
+        Schema(DecimalType.BigIntDecimal, nullable = true)
       case t if t <:< localTypeOf[Decimal] => Schema(DecimalType.SYSTEM_DEFAULT, nullable = true)
       case t if t <:< localTypeOf[java.lang.Integer] => Schema(IntegerType, nullable = true)
       case t if t <:< localTypeOf[java.lang.Long] => Schema(LongType, nullable = true)

sql/catalyst/src/main/scala/org/apache/spark/sql/types/DecimalType.scala

@@ -118,6 +118,7 @@ object DecimalType extends AbstractDataType {
   private[sql] val LongDecimal = DecimalType(20, 0)
   private[sql] val FloatDecimal = DecimalType(14, 7)
   private[sql] val DoubleDecimal = DecimalType(30, 15)
+  private[sql] val BigIntDecimal = DecimalType(38, 0)
 
   private[sql] def forType(dataType: DataType): DecimalType = dataType match {
     case ByteType => ByteDecimal