Tag Archives: Difference between

Java: Arrays vs Collections


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 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

JDBC : Difference between executeQuery() Vs executeUpdate() Vs execute() method


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

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