Core Java Interview Questions and Answers

Ques 71. What are the different level lockings using the synchronization keyword?

Ans.

• Class level lock 
• Object level lock 
• Method level lock 
• Block level lock

Ques 72. What is the use of PreparedStatement?

Ans. PreparedStatements are precompiled statements. It is mainly used to speed up the process of inserting/updating/deleting especially when there is a bulk processing.

Ques 73. What is callable statement? Tell me the way to get the callable statement?

Ans. CallableStatements are used to invoke the stored procedures. You can obtain the CallableStatement from Connection using the following methods prepareCall(String sql) prepareCall(String sql, int resultSetType, int resultSetConcurrency)

Ques 74. In a statement, I am executing a batch. What is the result of the execution?

Ans. It returns the int array. The array contains the affected row count in the corresponding index of the SQL.

Ques 75. Can a abstract method have the static qualifier?

Ans. No