Error when i remove a row after i add three rows

Question

i have a table component to some person
if i add 2 new rows to the table without commit changes,
after i remove them is works fine!
the problem is when i add more than 3 o more rows to the table and i want to remove some row it return error.
this is my code
add feature..
    public String insertar_action() {
        CachedRowSetDataProvider crs = getEncuestadoresDataProvider();
        RowKey fila = null;
        try{
            if(crs.canAppendRow()){
                fila = crs.appendRow();
                crs.setCursorRow(fila);
            }else{
                info("No se puede insertar una fila");
        }catch(Exception e){
            error("error : "+e);
        return null;
    }remove feature
public String borrar_action() {
        form1.discardSubmittedValues("guardar");
        CachedRowSetDataProvider crs1 = getEncuestadoresDataProvider();
        try {
            RowKey rk = tableRowGroup1.getRowKey();
            info("row key "+rk);
            if(rk!=null){
                crs1.removeRow(rk);
                crs1.commitChanges();
                crs1.refresh();
        } catch (Exception e) {
            info("No se pudo eliminar el registro!");
            info("error "+e);
        return null;
    }i hope somebody can help me
p.d. sorry my bad english
null

Answer 1

if i do a refresh after append a row, the row disappear immediately
the actions works fine with the new two rows added and deleted without information. and the actions works fine with others tables.
the problem begins when i add three or more new empty rows..
it's trying to execute a insert when i removeRow()
    * RowKey ;CachedRowSetRowKey[3]
    * error : java.lang.RuntimeException: Number of conflicts while synchronizing: 1 SyncResolver.INSERT_ROW_CONFLICT row 2 GDS Exception. 335544665. violation of PRIMARY or UNIQUE KEY constraint "INTEG_16242" on table "ENCUESTADORES"error when i remove the third.. fourth.. etc.. row (empty rows);
the print statement when i remove
INSERT INTO ENCUESTADORES (RUT, NOMBRE, APELLIDO, PASS, RUT_JEF) VALUES (?, ?, ?, ?, ?)
Writer:  executing insert , params:   Col[1]=(java.lang.String,)  Col[2]=(null:12)  Col[3]=(null:12)  Col[4]=(null:12)  Col[5]=(java.lang.String,33333333-3)
Writer:  executing insert , params:   Col[1]=(java.lang.String,)  Col[2]=(null:12)  Col[3]=(null:12)  Col[4]=(null:12)  Col[5]=(java.lang.String,33333333-3)