Does a distinctive constraint incorporate a not null constraint?

I've got a situation that certain attribute cellPhone could be NULL but can't be repeated, and so i provide 2 constraints: "not null" and "unique", inside a situation of upgrading the record, if user did not enter something I put within the area, therefore it makes this exception:

 SEVERE: java.sql.SQLIntegrityConstraintViolationException: ORA-00001: unique constraint (TEST1.OSQS_PARENTS_CELLPHONE_UK) violated

What must i do within the UPDATE situation?

EDIT here's the phrase table ddl

CREATE TABLE "TEST1"."OSQS_PARENTS" 
(   "PARENT_NO" NUMBER(38,0), 
"PARENT_NAME" VARCHAR2(4000 BYTE), 
"PARENT_ID" NUMBER(38,0), 
"PARENT_EMAIL" VARCHAR2(30 BYTE), 
"PARENT_CELLPHONE" NUMBER(38,0)
)

and here's a picture from the constraints enter image description here

here is the update statement

    Parent aParent;      //is an object I pass through a function
String SQlUpdate = "UPDATE OSQS_PARENTS P SET P.PARENT_ID=?,P.PARENT_EMAIL=?,P.PARENT_CELLPHONE=?"
            + " where P.PARENT_NO=?";
    PreparedStatement pstmt = null;
    try {
        pstmt = con.prepareStatement(SQlUpdate);
        pstmt.setLong(1, aParent.getId());
        pstmt.setString(2, aParent.getEmail());
        pstmt.setLong(3, aParent.getCellPhoneNo());
        pstmt.setLong(4, parentNo);

        pstmt.executeUpdate();
    }

it may sound such as this:

mobile phone should be unique. When user doesn't input value, you measure the level like a . As a result it fails whenever you attempt to place multiple values right into a 'UNIQUE' column.

In my opinion you have to drop the NOT NULL constraint around the column (ensure it is UNIQUE yes, but allow NULLS).

When user inputs no value, utilize it like a NO value (unknown = null <> -- is really a known value )

throw an IF to your statement, if value then that which you have, otherwise Place It TO NULL!

pstmt.setNull(3, java.sql.Types.INTEGER);