PreparedStatement.executeUpdate() currently does not work for DDL statements, and throws an exception. It should execute it successfully and return 0 as the result. (Ref)

String DDL = "CREATE TABLE FOO (ID INT64 NOT NULL, NAME STRING(100)) PRIMARY KEY (ID)";
try (PreparedStatement pstmt = connection.prepareStatement(DDL)) {
    int updateCount = pstmt.executeUpdate();
    assertEquals(updateCount, 0);
}

The above fails with the exception com.google.cloud.spanner.jdbc.JdbcSqlExceptionFactory$JdbcSqlExceptionImpl: INVALID_ARGUMENT: Statement is not an update statement: CREATE TABLE FOO (ID INT64 NOT NULL, NAME STRING(100)) PRIMARY KEY (ID).