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<>();
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Collections: This class contains exclusively static methods that work or return collection.
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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<>();
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HashSet: The HashSet is a collection of items in which every item is unique.
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HashTable:- The HashTable class implements a hash table, which maps keys to values.
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LinkedList: The LinkedList class Doubly Linked List implementation of the List and Deque interfaces.
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Objects: An Object can be defined as a character and behavior.
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Random: A random class can generate a list of random numbers.
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Scanner: A simple text scanner can parse primitive types and strings using regular expressions.
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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