Code360 powered by Coding Ninjas X Naukri.com. Code360 powered by Coding Ninjas X Naukri.com
Table of contents
1.
Introduction:
2.
What is a package?
3.
What is the java.util package?
4.
Use of java.util In java?
5.
Some important used classes.
6.
Frequently Asked Questions:
7.
Key Takeaways:
Last Updated: Mar 27, 2024

java.util package

Crack Google SDE interview : Essential projects
Speaker
Saurav Prateek
SDE-2 @
20 Jun, 2024 @ 01:30 PM

Introduction:

The Package java.util contains incidental utility classes, related connection points, and exceptional cases. It incorporates nonexclusive data structures like Hashtable, Stack, string control, arbitrary number age, framework properties, warning and list of data structures, and calendar and date utilities.

Recommended Topic-  Iteration Statements in Java, Duck Number in Java and Hashcode Method in Java.

What is a package?

A Package can be defined as a collection of similar classes, interfaces, and sub-packages in the directory structure. In simple words, you can say the Java package is used to group related classes. To use this import keyword is required. 

import java.util.Scanner

Also see, Swap Function in Java

Get the tech career you deserve, faster!
Connect with our expert counsellors to understand how to hack your way to success
User rating 4.7/5
1:1 doubt support
95% placement record
Akash Pal
Senior Software Engineer
326% Hike After Job Bootcamp
Himanshu Gusain
Programmer Analyst
32 LPA After Job Bootcamp
After Job
Bootcamp

What is the java.util package?

It is a Java package like other packages in Java. It is the one that contains Java collections framework classes. The import is a Java keyword used for importing a Java class or entire package. For eg.

import java.util.Calender

Use of java.util In java?

The Java util (java.util) package contains a collection framework. It contains collection classes, date and time, event models, and various utility classes. You can use all these classes and methods on importing this (java.util) package. 

The use of java. util package is as follows:

  • It can be used for Java collections.
  • It can be used for internalization-supported classes from this package.
  • It can be used for random number generation.
  • It can be used for string parsing.
  • It can be used for base64 encoding and decoding.

Some important used classes.

  •  Arrays: This class consists of various methods for manipulating arrays.
import java.util.Arrays;
int[] arr = new int[n];
  • ArrayList: This class implements the resizable-array list interface.
import java.util.ArrayList;
ArrayList<Integer> list = new ArrayList<>();
  • Collections:  This class contains exclusively static methods that work or return collection.
     
  • Date: This class addresses a particular moment on schedule with millisecond accuracy.
     
  • HashMap: The HashMap class Hash table-based execution of the Map interface.
import java.util.HashMap;
HashMap<string, Integer> map = new HashMap<>();
  • HashSet: The HashSet is a collection of items in which every item is unique. 
     
  • HashTable:- The HashTable class implements a hash table, which maps keys to values.
     
  • LinkedList: The LinkedList class Doubly Linked List  implementation of the List and Deque interfaces.
     
  • Objects: An Object can be defined as a character and behavior.
     
  • Random:  A random class can generate a list of random numbers.
     
  • Scanner: A simple text scanner can parse primitive types and strings using regular expressions.
     
  • StringTokenizer: String tokenizer allows you to break a String into tokens.
     
  • TreeSet: The TreeSet class A NavigableSet implementation based on a TreeMap.

 

Must Read Difference between ArrayList and LinkedList

Practice by yourself on online java compiler.

You can also check about Java Tokens here.

Must Read Difference between ArrayList and LinkedList

Frequently Asked Questions:

Q: What is the use of the Java util package?

A: It provides the classes necessary to create an applet that communicates with its applet context. It contains all the classes for building user interfaces and painting graphics and images.

Q: Why do we use import Java util.*?

A: It means importing all the classes and interfaces within java.util package and making them available within the current class or interface. This is shorthand wild card annotation for importing all classes within a particular package.

Key Takeaways:

In this blog, we have covered several topics, which are:

Read about Interface in Java here

  • What is a package?
  • What is java.util package and how to import a specific package.
  • Features and application of java.util package.
  • Some important used classes along with their functionalities.

If you want to learn more about different packages, please visit our website, Packages in Java

Previous article
User Defined Packages in Java
Next article
The java.lang Package
Live masterclass