Import statement usage in Java - Cheat Sheet & Quick Revision

overview

Recall & Review

beginner

What is the purpose of an import statement in Java?

An import statement allows you to use classes and interfaces from other packages without writing their full package names every time.

beginner

How do you import all classes from a package named <code>java.util</code>?

You use <code>import java.util.*;</code> to import all classes from the <code>java.util</code> package.

beginner

True or False: You can import a single class using its full package name.

True. For example, <code>import java.util.ArrayList;</code> imports only the <code>ArrayList</code> class.

beginner

What happens if you don't use an import statement but want to use a class from another package?

You must use the full package name every time you refer to the class, like java.util.ArrayList instead of just ArrayList.

beginner

Can you import classes from the same package using an import statement?

No, classes in the same package are accessible without import statements.

Which import statement imports all classes from the java.io package?

A import java.io;

B import java.io.*;

C import * from java.io;

D import java.io.all;

What is the correct way to import only the Scanner class from java.util?

A import java.util.Scanner;

B import java.util.*;

C import Scanner from java.util;

D import java.util.Scanner.*;

If you do not import a class, how can you still use it?

A By using a wildcard import

B By guessing the class name

C By writing its full package name every time

D By declaring it again

Can you import a class from the same package?

A Only if the class is private

B Yes, always required

C Only if the class is public

D No, it is not necessary

What does the import statement import java.util.*; do?

A Imports all classes in java.util package

B Imports only the java.util package itself

C Imports all sub-packages of java.util

D Imports only the first class in java.util

Explain why import statements are useful in Java and how they simplify code.

Describe the difference between importing a single class and using a wildcard import.