How to get the insert ID in JDBC?

If it is an auto generated key, then you can use Statement#getGeneratedKeys() for this. You need to call it on the same Statement as the one being used for the INSERT. You first need to create the statement using Statement.RETURN_GENERATED_KEYS to notify the JDBC driver to return the keys.

Here's a basic example:

public void create(User user) throws SQLException {    try (        Connection connection = dataSource.getConnection();        PreparedStatement statement = connection.prepareStatement(SQL_INSERT,                                      Statement.RETURN_GENERATED_KEYS);    ) {        statement.setString(1, user.getName());        statement.setString(2, user.getPassword());        statement.setString(3, user.getEmail());        // ...        int affectedRows = statement.executeUpdate();        if (affectedRows == 0) {            throw new SQLException("Creating user failed, no rows affected.");        }        try (ResultSet generatedKeys = statement.getGeneratedKeys()) {            if (generatedKeys.next()) {                user.setId(generatedKeys.getLong(1));            }            else {                throw new SQLException("Creating user failed, no ID obtained.");            }        }    }}

Note that you're dependent on the JDBC driver as to whether it works. Currently, most of the last versions will work, but if I am correct, Oracle JDBC driver is still somewhat troublesome with this. MySQL and DB2 already supported it for ages. PostgreSQL started to support it not long ago. I can't comment about MSSQL as I've never used it.

For Oracle, you can invoke a CallableStatement with a RETURNING clause or a SELECT CURRVAL(sequencename) (or whatever DB-specific syntax to do so) directly after the INSERT in the same transaction to obtain the last generated key. See also this answer.

1. Create Generated Column

   String generatedColumns[] = { "ID" };

2. Pass this geneated Column to your statement

   PreparedStatement stmtInsert = conn.prepareStatement(insertSQL, generatedColumns);

3. Use ResultSet object to fetch the GeneratedKeys on Statement

   ResultSet rs = stmtInsert.getGeneratedKeys();if (rs.next()) {    long id = rs.getLong(1);    System.out.println("Inserted ID -" + id); // display inserted record}

I'm hitting Microsoft SQL Server 2008 R2 from a single-threaded JDBC-based application and pulling back the last ID without using the RETURN_GENERATED_KEYS property or any PreparedStatement. Looks something like this:

private int insertQueryReturnInt(String SQLQy) {    ResultSet generatedKeys = null;    int generatedKey = -1;    try {        Statement statement = conn.createStatement();        statement.execute(SQLQy);    } catch (Exception e) {        errorDescription = "Failed to insert SQL query: " + SQLQy + "( " + e.toString() + ")";        return -1;    }    try {        generatedKey = Integer.parseInt(readOneValue("SELECT @@IDENTITY"));    } catch (Exception e) {        errorDescription = "Failed to get ID of just-inserted SQL query: " + SQLQy + "( " + e.toString() + ")";        return -1;    }    return generatedKey;} 

This blog post nicely isolates three main SQL Server "last ID" options: http://msjawahar.wordpress.com/2008/01/25/how-to-find-the-last-identity-value-inserted-in-the-sql-server/ - haven't needed the other two yet.