DatabaseMetaData on version 5.5

Migrate my test application failed due to DatabaseMetaData.

My test snippet as below:

String[] JDBC_METADATA_TABLE_TYPES = {"TABLE"};
Class.forName("com.google.appengine.api.rdbms.AppEngineDriver");
conn = DriverManager.getConnection(url, user, password);

String tableName = ...;

DatabaseMetaData databaseMetaData = conn.getMetaData();
ResultSet tables = databaseMetaData.getTables(null, null, tableName,
JDBC_METADATA_TABLE_TYPES);
boolean existed = tables.next();
// on my old mySQL instance (v5.1): existed = true
// on my new mySQL instance (v5.5): existed = false

I am sure the table tableName is existed in both instances.

Any help is appreciated.