Oracle maps all native types and User Defined Types (UDTs) to Java types. When you use SQLData you map individual components and structures. The following table notes how Oracle types map to Java types:

SQL Data Types	Java Class Data Types
CHAR	oracle.sql.CHAR
LONG	java.lang.String
VARCHAR2	java.lang.Byte
	java.lang.Short
	java.lang.Integer
	java.lang.Long
	java.lang.Float
	java.lang.Double
	java.lang.BigDecimal
	java.sql.Date
	java.sql.Time
	java.sql.Timestamp
	byte
	short
	int
	long
	float
	double
DATE	oracle.sql.DATE java.lang.String java.sql.Date java.sql.Time java.sql.Timestamp
NUMBER	oracle.sql.NUMBER java.lang.Byte java.lang.Short java.lang.Integer java.lang.Long java.lang.Float java.lang.Double java.lang.BigDecimal byte short
	int
	long float
	double
OPAQUE	oracle.sql.OPAQUE
RAW LONG RAW	oracle.sql.RAW byte[]
ROWID	oracle.sql.CHAR oracle.sql.ROWID java.lang.String
BFILE	oracle.sql.BFILE
BLOB	oracle.sql.BLOB oracle.jdbc.Blob (JDK 1.1.x
CLOB NCLOB	oracle.sql.CLOB oracle.jdbc.Clob (JDK 1.1.x
OBJECT Object types	oracle.sql.STRUCT java.sql.Struct (JDK 1.1.x)
	java.sql.SQLData
	oracle.sql.ORAData
REF	oracle.sql.REF
Reference types	java.sql.Ref (JDK 1.1.x)
	oracle.sql.ORAData
TABLE	oracle.sql.ARRAY
VARRAY	java.sql.Array (JDK 1.1.x)
Nested table and types	oracle.sql.ORAData
VARRAY types
Any of the preceding	oracle.sql.CustomDatum
SQL types	oracle.sql.Datum

Native types and UDTs can be used and managed by the SQLData conventions covered in the chapter. The Oracle JPublisher tool enables you to develop SQLData stubs and programs to use your UDTs.

Summary

You should now have an understanding of how to implement and troubleshoot server-side or internal Java class libraries. With these skills, you can build robust solutions in Java, affording you a certain simplicity over using PL/SQL.