Answer / manja

LinkedHashSet, TreeSet and HashSet are three of most popular implementation of Set interface in Java Collection Framework. Since they implement Set interface, they follow it's contract for not allowing duplicates. All these implementation except, TreeSet uses equals() method to check for duplicates, on the other hand TreeSet use compareTo() or compare() method for comparing objects and can break Set interface contract of unique element, if equals method is not consistent with compareTo() or compare() method. In this Java Collection tutorial, we will see difference between LinkedHashSet vs TreeSet vs HashSet on different points e.g. speed, performance, ordering, synchronization etc. Based upon these differences we can also decide when to use LinkedHashSet vs TreeSet vs HashSet in Java. TL;DR, Use HashSet for all general purpose usage i.e. where you need to store only unique elements without any ordering requirement. If you need to maintain order on which elements are added into Set then use LinkedHashSet, it provides ordering with little impact on performance. Use TreeSet when you absolutely nee to keep elements in specific sorted order e.g. keeping employee in increasing order of their age or salary. Remember, TreeSet is significantly slower than LinkedHashSet and HashSet because of this sorting overhead.

What is deque in the java collections framework? : java collections

0 Answers  

---

Hi Friends , am newbie to ajax. For example just consider one account registration - A form contains 8 text fields with submit button. In this form second texbox contains "username " . On right side of text box there is a label box . On clilck action i need to determine user is available or not. Is it possible on clicking label or should i click submit button.

0 Answers  

---

what is diff string and stringbuffer

7 Answers   CTS, HCL,

---

Which of the following declaration is wrong? int i=45; float j = 45.0; double k=45.0;

5 Answers   Adobe,

---

who will give req's to u?. how they send req's to u? . what design documents contains?. when bugs raised on other developer code how to report to them?.(throgh mail or ........). how to retrive 100 recods from dao layer to presentation layer.using which collection?. what is sequence diagram.?.

0 Answers   iGate,

---

wnet use DAO design in u r project?

1 Answers   Godrej,

---

Explain the OOPS concept in Realtime Scenarion ? Take example as CAR. Please explain indetail ?

0 Answers   Cap Gemini,

---

what is java virtual machine

4 Answers  

---

when exactly should we use throws ,and wen exactly should we use the try and catch for exceptional handling

0 Answers  

---

Write a interface "CarOperations" with the following methods void turnOnEngin() void turnOffEngin() void turnOnLigths() void turnOffLights() void turnLeft() void turnRight() void accelerate() void deaccelerate() void putBreaks() void releaseBreaks()

1 Answers  

---

What causes Out of Memory exception?

5 Answers   CTS,

---

Which is the better framework for web applications, struts or spring, and why?

1 Answers   IBM, TATA,

---