Java: can integer = null be set?
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Java
If this parameter exists in the database, I have a function that returns the ID number If not, null Is this begging for a null pointer exception? Negative signs are not allowed, but I think it would be clearer if non-existent parameters returned null instead of error codes like - 1 What's your opinion?
private Integer tidOfTerm(String name) throws sqlException { String sql = "SELECT tid FROM term_data WHERE name = ?"; PreparedStatement prep = conn.prepareStatement(sql); prep.setString(1,name); ResultSet result = prep.getResultSet(); if (result.next()) { return result.getInt("tid"); } return null; // TODO: is this begging for a null pointer exception? }
Solution
This is perfectly legal If you want to avoid NPE, throw a custom exception But don't return negative numbers If the caller does not check the return value, you will always have a problem But doing the wrong calculation (because the result ratio is multiplied by - 1) is definitely more difficult to debug than non - caught exceptions
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