Problem with prepareStatement and Statement.RETURN_GENERATED_KEYS in PostgreSQL JDBC driver 8.4

When using 8.4 JDBC drivers, calling prepareStatement(String sql, int
autoGeneratedKeys) with Statement.RETURN_GENERATED_KEYS seems to add
"RETURNING *" to the end of the SQL even with select statements.
According to Javadoc for prepareStatement(String sql, int
autoGeneratedKeys) in java.sql.Connection:

"The given constant tells the driver whether it should make
auto-generated keys available for retrieval. This parameter is ignored
if the SQL statement is not an INSERT statement, or an SQL statement
able to return auto-generated keys (the list of such statements is
vendor-specific). "

Here's a simple test class to demonstrate this problem:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;

public class PostgrePrepareStatementTest {

    public static void main(String[] args) throws
InstantiationException, IllegalAccessException, ClassNotFoundException,
SQLException {
        Class.forName("org.postgresql.Driver").newInstance();
        String url = "jdbc:postgresql://localhost:5432/testdb";
        Connection conn = DriverManager.getConnection(url, "user",
"password");
        PreparedStatement pStmt = conn.prepareStatement("select * from
test_table", Statement.RETURN_GENERATED_KEYS);
        System.out.println(pStmt.toString());
        pStmt.execute();
    }
}


When run this prints "select * from test_table RETURNING *" -  which is
invalid - and an exception is thrown:

Exception in thread "main" org.postgresql.util.PSQLException: ERROR:
syntax error at or near "RETURNING"
  Position: 26
    at
org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2062)
    at
org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1795)
    at
org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
    at
org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:479)
    at
org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:367)
    at
org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:360)
    at
com.smilehouse.PostgrePrepareStatementTest.main(PostgrePrepareStatementTest.java:17)

I have tested this with driver version 8.4-701 (both JDBC3 and JDBC4).
The PostgreSQL version was 8.4.

-Heikki Hiltunen