CODEWITHSUNDEEP
java
Kartik Kakadiya
Kartik Kakadiya

Reputation: 13

Among java.util.* and java.util.Scanner, performance wise which one is better?

java.util.* import all the class under it, while java.util.Scanner only imports Scanner class. So, is there any difference between them in time of execution between them?

Upvotes: 1

Views: 1835

Answers (2)

Sweeper
Sweeper

Reputation: 272760

Unlike the #include thingy in C, importing stuff in Java does not actually copy stuff, so performance-wise, java.util.* and java.util.Scanner are practically the same.

However, importing everything from a package can cause name conflicts. Look at how many classes there are that are called Scanner:

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If you just so happens to import everything from both java.util and sun.tools.java. The compiler will not be able to infer which Scanner you are referring to.

Upvotes: 2

Rupesh Bharuka
Rupesh Bharuka

Reputation: 91

java.util.* will import the entire utility classes whereas java.util.Scanner will import only Scanner class. Now, it is up to you as if you want to take input from user then import only java.util.Scanner class specifically.

It is always best practice to import specific class because importing entire package may confuse you. Eg java has 2 Date classes in two different packages 1)java.util.Date 2)java.sql.Date

When we import an entire package using '*' and if any error occurs then we don't understand because of which class this error has occurred that's why it is always best practice to import specific class according to the requirement.

Thank you. Rupesh R. Bharuka

Upvotes: 0

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