// Connect to the database.
Connection conn = DriverManager.getConnection(URL, USER, PASS);
// Construct the SQL statement we want to run, specifying the parameter.
String sql = "SELECT * FROM users WHERE email = ?";
// Generate a prepared statement with the placeholder parameter.
PreparedStatement stmt = conn.prepareStatement(sql);
// Bind email value into the statement at parameter index 1.
stmt.setString(1, email);
// Run the query...
ResultSet results = stmt.executeQuery(sql);
while (results.next())
{
// ...do something with the data returned.
}