DERBY-6125 Code clean up in client driver.
Patch derby-6125-05-d; details:

** ClientXid

- reworked ClientXid#equals to find favor with FindBugs: now tests for null and wrong type.
  The old version would get classcastexception if a wrong type object was compared.

- made ClientXid#getData clone the result - it is a byte array

** Section

- clone bytes in Section#setPKGNAMCBytes to avoid having a package private variable
  wriable from outside the package (it's an array).

- make Section#getPKGNAMCBytes return a clone

** Sqlca

- removed unnecessary a priori allocation to Sqlca#sqlErrd_.

- made Sqlca#sqlWarn_ private

- changed #getSqlWarn to return String since all its uses need a String anyway.

- made Sqlca#getSqlErrd private

- simplified implementation of Sqlca#getSqlWarn

- made Sqlca#rowsetRowCount_ private

- made Sqlca#containsSqlcax_ private

- made Sqlca#sqlErrmcMessages_ private

- removed argument sqlErrpBytes from Sqlca#setContainsSqlcax (only called once; with null).

- removed argument sqlErrpBytes from Sqlca#resetRowsetSqlca  (only called with null).

- introduced Sqlca#getReturnValue in Statement#completeExecute instead
  of allowing access to sqlca.getSqlErrd()[0]

- removed unused Sqlca#sqlErrmcCcsid_

- introduced public String Sqlca#formatSqlErrd as replacement for
  direct access to Sqlca#sqlErrd_.

** NetSqlca

- made NetSqlca#setSqlwarnBytes package private

- made NetSqlca#setSqlerrmcBytes package private and removed its
  argument sqlErrmcCcsid

- made NetSqlca#setSqlerrd package private

- removed unnecessary test for BIG_ENDIAN in NetSqlca#getRowCount: the
  protocol always uses big endian (SignedBinary.BIG_ENDIAN = 1 is final).

- removed unnecessary type argument to NetSqlca#getRowCount now that endian test is no longer done

** Statement

- made Statement#materialStatement_ private; new accessors

** NetConnection

- removed unnecessary default NetConnection finalizer

- three methods in NetConnection do nothing except calling the method with the same name in the super class:

  - close()
  - closeX()
  - closeResources()

  Remove them and let NetConnection inherit them from its super class.

- Since we remove these methods from NetConnection, we also make
  Connection.closeX() private and unsynchronized, as it will only be
  called from Connection.close().

- NetConnection's closeForReuse() method doesn't have any callers;
  remove that one too.

- NetConnection.completeConnect() doesn't actually do anything except
  calling super.completeConnect(). Remove the override and make the
  super method final instead.

** NetXAConnection

- removed potentially harmful finalizer in NetXAConnection: it calls a
  finalizer for another class (NetConnection). FindBugs advice on this
  (quote):

  "If a connected set of objects beings finalizable, then the VM will
  invoke the finalize method on all the finalizable object, possibly
  at the same time in different threads. Thus, it is a particularly
  bad idea, in the finalize method for a class X, invoke finalize on
  objects referenced by X, because they may already be getting
  finalized in a separate thread. "

  It also neglected to call super.finalize()...

** Typdef

- made Typdef#FdocaSimpleDataArray private

- removed unused TypDef#getByteOrder

- made Typdef#environmentTables_ private

** SqlException

- made SqlException#SQLExceptionFactory package private (was protected)

** EncryptionManager

- removed unused methods EncryptionManager#setInitVector and #setSecKey

** NetXACallInfo

- removed unused NetXACallInfo#getCorrelatorToken

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1465193 13f79535-47bb-0310-9956-ffa450edef68