Import Statements

Import Statements with examples:

Let me explain import statement with an example

Example 1:

class Test

{

public static void main(String[] agrs)

{

                Arraylist al=new Arraylist();

}

}

Compile time error cannot find symbol symbol: class Arraylist Location: class Test

This issue can be resolved in two ways:

Sol1: Using fully qualified name like java.util.Arraylist al=new java.util.Arraylist();

Sol2: Importing java.util.Arraylist like import java.util.Arraylist; (this is the preferred solution)

Types of import:

•   .       Explicit class import 
•               Implicit class import

Explicit class import: example is import java.util.Arraylist;

 It is highly recommended to use explicit class import because it increases the readability of the code.

Implicit class import: example is import java.util.*;

It is not recommended as it reduces the readability of the code.

Example of Implicit class import:

Example1:

import java.util.*;

import java.sql.*;

class Test

{

                public static void main(String[] args)

                {

                                Date d=new Date();

                }

}              

Compile time error “reference to Date is ambiguous”.

We are getting this ambiguity problem as Data is available in both util and sql package. So it is recommended to use explicit class import

Example2:

import java.util.Date;

import java.sql.*;

class Test

{

                public static void main(String[] args)

                {

                                Date d=new Date();

                }

}

Util package Date will be considered

While resolving class name compiler uses the following precedence

1.       Explicit class import

2.       Classes present in present working directory

3.       Implicit class import