In Java, Arrays and Collections both are to deal with a group of objects but there are lots of differences in terms of data structure or performing operations.
Here are some most common differences:
Difference between Arrays & Collections
|Arrays is having fixed-length..
||Collections are growable in nature i.e increase or decrease.
|Arrays are not recommended in terms of memory concerns.
||Collections use different data structures and recommended to use with respect to memory.
|Arrays are used with respect to performance.
||Collections are not recommended to use with respect to performance.
|Arrays can store only homogeneous (same type) of data.
||Collections can hold both homogeneous and heterogeneous elements.
|Arrays do not have a single API.
||Collections having big list of methods.
|Arrays can work with primitives and object types.
||Collections can hold only objects but not with primitive. If you pass as primitive internally convert to object.
|See Also: Array & Arrays Class Examples
||See Also: Collection Framework and Examples
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()
|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.
DML->INSERT , UPDATE and DELETEDDL-> CREATE, ALTER
|Any Type of SQL statements.
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