executeQuery(), executeUpdate() and execute() are the methods of java.sql.Statement interface of JDBC API which are used to execute the SQL statements.

executeQuery() Vs executeUpdate() Vs execute()

executeQuery()	executeUpdate()	execute()
This method is use to execute the SQL statements which retrieve some data from database.	This statement is used to execute SQL statements which update or modify database.	This method can be use for any kind of SQL statements.
This method returns a ResultSet object which contains the result returned by query.	This method returns an int value which represent number of rows affected by the query. This will be 0 for statement which are returning nothing.	This method return a Boolean value. TRUE indicates that query returned a ResultSet object and FALSE indicate returned an int value or returned nothing.
This method is use to execute select query.	This method is use to execute non select query.	This method is use to execute select and non select queries.
Ex: SELECT	Ex: DML->INSERT , UPDATE and DELETEDDL-> CREATE, ALTER	Any Type of SQL statements.

More on JDBC

Follow below links to know more on JDBC and solving JDBC issues :

• JDBC Tutorial
• JDBC Sample Code
• JDBC Issues and Solutions
• JDBC Interview Questions And Answers
• JDBC Coding Best Practices