Set long 10000 é um comando SQL*PLUS, não um SQL padrão, é por isso que você encontrou o erro. Exemplo
ResultSet rs = stmt.executeQuery("SELECT DBMS_METADATA.GET_DDL('TABLE','YOUR_OBJECTS','JAY') as ddl FROM dual");
while(rs.next()){
System.out.println(rs.getString(1));
}
Saída
CREATE TABLE "JAY"."YOUR_OBJECTS"
( "OWNER" VARCHAR2(128) NOT NULL ENABLE,
"OBJECT_NAME" VARCHAR2(128) NOT NULL ENABLE,
"SUBOBJECT_NAME" VARCHAR2(128),
"OBJECT_ID" NUMBER NOT NULL ENABLE,
"DATA_OBJECT_ID" NUMBER,
"OBJECT_TYPE" VARCHAR2(23),
"CREATED" DATE NOT NULL ENABLE,
"LAST_DDL_TIME" DATE NOT NULL ENABLE,
"TIMESTAMP" VARCHAR2(19),
"STATUS" VARCHAR2(7),
"TEMPORARY" VARCHAR2(1),
"GENERATED" VARCHAR2(1),
"SECONDARY" VARCHAR2(1),
"NAMESPACE" NUMBER NOT NULL ENABLE,
"EDITION_NAME" VARCHAR2(128),
"SHARING" VARCHAR2(13),
"EDITIONABLE" VARCHAR2(1),
"ORACLE_MAINTAINED" VARCHAR2(1)
) SEGMENT CREATION IMMEDIATE
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
NOCOMPRESS LOGGING
STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "ORAPDB1_TBS1"
Eu obtive DDL parcial ao executar a mesma instrução no SQL*PLUS.
SQL> SELECT DBMS_METADATA.GET_DDL('INDEX','SYS_IL0000092981C00086$$','JAY') as ddl FROM dual;
DDL
--------------------------------------------------------------------------------
CREATE UNIQUE INDEX "JAY"."SYS_IL0000092981C00086$$" ON "JAY"."SYS_EXPORT_SCH
Aqui eu posso obter o DDL inteiro definindo
SET LONG MAS eu recebo uma saída completa no aplicativo Java. Saída(Eclipse)
CREATE UNIQUE INDEX "JAY"."SYS_IL0000092981C00086$$" ON "JAY"."SYS_EXPORT_SCHEMA_01" (
PCTFREE 10 INITRANS 2 MAXTRANS 255
STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "ORAPDB1_TBS1"
PARALLEL (DEGREE 0 INSTANCES 0)
