Update DefaultTAPErrorWriter.java

[denaliak]

TAP service returns an invalid error document, which is not parsable.

When running the TAP query with a syntax error in 'async' mode, e.g. "SELECT TOP 1000 FROM TAP_SCHEMA.schemas" (missing ''), The error page created would include two INFO element, namely, 'CAUSES' and 'ORIGIN_STACK_TRACE', as follows: <INFO name="CAUSES" value="1"> - Encountered "FROM". Was expecting one of: "(" "+" "-" "" "AVG" "MAX" "MIN" "SUM" "COUNT" "BOX" "CENTROID" "CIRCLE" "POINT" "POLYGON" "REGION" "CONTAINS" "INTERSECTS" "AREA" "COORD1" "COORD2" "COORDSYS" "DISTANCE" "ABS" "CEILING" "DEGREES" "EXP" "FLOOR" "LOG" "LOG10" "MOD" "PI" "POWER" "RADIANS" "RAND" "ROUND" "SQRT" "TRUNCATE" "ACOS" "ASIN" "ATAN" "ATAN2" "COS" "COT" "SIN" "TAN" "'" <SCIENTIFIC_NUMBER> <UNSIGNED_FLOAT> <UNSIGNED_INTEGER> """ <REGULAR_IDENTIFIER_CANDIDATE> <REGULAR_IDENTIFIER_CANDIDATE> """ (HINT: "FROM" is a reserved ADQL word. To use it as a column/table/schema name/alias, write it between double quotes.) </INFO> <INFO name="ORIGIN_STACK_TRACE" value="2"> adql.parser.ParseException: Encountered "FROM". Was expecting one of: "(" "+" "-" "*" "AVG" "MAX" "MIN" "SUM" "COUNT" "BOX" "CENTROID" "CIRCLE" "POINT" "POLYGON" "REGION" "CONTAINS" "INTERSECTS" "AREA" "COORD1" "COORD2" "COORDSYS" "DISTANCE" "ABS" "CEILING" "DEGREES" "EXP" "FLOOR" "LOG" "LOG10" "MOD" "PI" "POWER" "RADIANS" "RAND" "ROUND" "SQRT" "TRUNCATE" "ACOS" "ASIN" "ATAN" "ATAN2" "COS" "COT" "SIN" "TAN" "'" <SCIENTIFIC_NUMBER> <UNSIGNED_FLOAT> <UNSIGNED_INTEGER> """ <REGULAR_IDENTIFIER_CANDIDATE> <REGULAR_IDENTIFIER_CANDIDATE> """ (HINT: "FROM" is a reserved ADQL word. To use it as a column/table/schema name/alias, write it between double quotes.) at adql.parser.ADQLParser.generateParseException(ADQLParser.java:6320) at adql.parser.ADQLParser.jj_consume_token(ADQLParser.java:6180) at adql.parser.ADQLParser.SelectItem(ADQLParser.java:1318) at adql.parser.ADQLParser.Select(ADQLParser.java:1162) at adql.parser.ADQLParser.QueryExpression(ADQLParser.java:1051) at adql.parser.ADQLParser.Query(ADQLParser.java:1010) at adql.parser.ADQLParser.parseQuery(ADQLParser.java:451) at tap.ADQLExecutor.parseADQL(ADQLExecutor.java:571) at tap.ADQLExecutor.start(ADQLExecutor.java:366) at tap.ADQLExecutor.start(ADQLExecutor.java:226) at tap.AsyncThread.jobWork(AsyncThread.java:81) at uws.job.JobThread.run(JobThread.java:430)

These two INFO elements contain free text that is not parsable by the xml parser, resulting in an error. You can try this out on TOPCAT. The error I am getting from the parser is
The element type "REGULAR_IDENTIFIER" must be terminated by the matching end-tag "</REGULAR_IDENTIFIER>".

To fix it, CDATA (Character Data that should not be interpreted as XML markup) should be used around all free text:

or whatever ]]>