How are emptySet(), singleton & unmodifiable methods in Java Collections useful?

Asked by Last Modified  

1 Answer

Learn Java

Follow 0
Answer

Please enter your answer

Surya Prabha

Java Expertise

"emptySet()" is used to return empty and unmodifiable set. Instead of deals with returning null it will return empty. we can avoid nullpointerexception. Also returned empty set is unmodifiable we will get UnsupportedOperationException if we try to modify. All unmodifiable methods like Collections.unmodifiableSet,Collections.unmodifiableList,Collections.unmodifiableMap...
read more
"emptySet()" is used to return empty and unmodifiable set. Instead of deals with returning null it will return empty. we can avoid nullpointerexception. Also returned empty set is unmodifiable we will get UnsupportedOperationException if we try to modify. All unmodifiable methods like Collections.unmodifiableSet,Collections.unmodifiableList,Collections.unmodifiableMap will return unmodifiable list,set,map and whenever we will get the scenario that the client or any third party vendor should not allow to modify list or set or map once it get generated we can go for unmodifiable methods.It allows us to share a list, set or map with another objects without giving them the possibility to modify them, while we can manipulate them as required. "Collections.singleton" this method is to remove an element from Collections like List and Set at once. Let as take Example, I have list {1,2,5,2,4,9,2} if i try to remove '2' without using singleton i will get result as, Remove 2 without using singleton:{1,5,2,4,9,2} Remove 2 with using singleton:{1,5,4,9} it will remove all '2' at once. read less
Comments
Dislike Bookmark

Related Questions

I am looking for live project trainer for Java j2ee near Hinjewadi ph 3 or near Bavdhan. Thanks
I am a passoniate software enginner and a professional trainer. I can provide support for your live project.
Richa
What are the benefits of attending Java coaching classes?
Java is good programming language and more powerful. if you need to learn good concept of programming then Java is best because you need to write your own code manually. there are many other IDE which...
Selvi
0 0
5
I want to know what are the differences between runnable and thread class implementation except they are class and interface and how to decide which is better at what time ...
Thread vs. Runnable in Java 1) Java doesn't support multiple inheritance, which means you can only extend one class in Java so once you extended Thread class you lost your chance and can not extend...
Ankit Garg

I am a fresher and I want to become a Java developer, so what is necessary to crack the Java interview ? 
Hi Dipesh, understand that Java is a kind of ocean. It is vast. For interview preparation, you can brush up your Core Java Concepts and OOPs concepts and understand how JAVA works and learn the java features...
Dipesh
What will be the output of the program? public class Test { public static int y; public static void foo(int x) { System.out.print("foo "); y=x; } public static int bar(int z) { System.out.print("bar "); return y=z; } public static void main(String [] args ) { int t=0; assert t > 0 : bar(7); assert t > 1 : foo(8); /* Line 18 */ System.out.println("done "); } } A. bar B. bar done C. foo done D. Compilation fails
Compiler error on line 18. You can't call method in assert with void return type.
Srikanth

Now ask question in any of the 1000+ Categories, and get Answers from Tutors and Trainers on UrbanPro.com

Ask a Question

Related Lessons

Syntax and example of java
Java syntax: Class Display - - class definition { Void Display() { System.out.println('welcome to Java') ; } Public static void main(String arcs) { Display D=new Display() ;--object creation D. Display } }

Semalla Santosh Kumar

0 0
0
Understanding concept of Inheritance in Java
Inheritance: Acquiring a properties and methods from Parent class to Child class. For example, In some cases we can hear from any one of your relative or your friends will say like that "You are bahaving...

Uday Ch

0 0
0
Spring Framework Mvc

Chinmay Patel

0 0
0
Use of Service Locator Pattern
If we want to reuse the java code that should be the best approach w.r.t re-usability, maintanence and saving time to concentrate on our own businbess logic/requirement. In the similar approach many patterns...

Milan M.

0 0
0
How to create a Singleton class?
How to create a Singleton class: Q) What is a singleton class? A) In simple words, a singleton class is a class which can have only one instance at any point of time throughout the application and provides...

Gpcomptech

0 0
0

Recommended Articles

Top 5 Reasons to Learn JavaScript

Before we start on the importance of learning JavaScript, let’s start with a short introduction on the topic. JavaScript is the most popular programming language in the world, precisely it is the language - for Computers, the Web, Servers, Smart Phone, Laptops, Mobiles, Tablets and more. And if you are a beginner or planning...

Read full article >

Why Java is the Most Popular Programming Language

Designed in a flexible and user-friendly demeanor, Java is the most commonly used programming language for the creation of web applications and platform. It allows developers to “write once, run anywhere” (WORA). It is general-purpose, a high-level programming language developed by Sun Microsystem. Initially known as an...

Read full article >

Some Popular IT Courses in Current Market

In the domain of Information Technology, there is always a lot to learn and implement. However, some technologies have a relatively higher demand than the rest of the others. So here are some popular IT courses for the present and upcoming future: Cloud Computing Cloud Computing is a computing technique which is used...

Read full article >

Why Should You Learn Java !

Java is the most famous programming language till date. 20 years is a big time for any programming language to survive and gain strength. Java has been proved to be one of the most reliable programming languages for networked computers. source:techcentral.com Java was developed to pertain over the Internet. Over...

Read full article >

Find Java Certification near you
Java Certification in Bangalore
Java Certification in Hyderabad
Java Certification in Pune
Java Certification in Chennai
Java Certification in Delhi
Java Certification in Mumbai
Java Certification in Kolkata
Java Certification in Noida
Java Certification in Gurgaon
Java Certification in Ghaziabad
Online Java Training

Looking for Java Training Classes?

Learn from the Best Tutors on UrbanPro

Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you