JAVA Collection and generics
- 1. Java : Collection and Introduction to Generics Developer Students Club - LNCT
- 2. What is collection ? The image shows a collection of watches.
- 3. 1. Intro A collection is an object that represents a group of objects (such as the classic Vector class). A collections framework is a unified architecture for representing and manipulating collections, enabling collections to be manipulated independently of implementation details.
- 4. Advantages of using collection ? Tip In this question, Think of real world example Try to think the benefits of handling things as a group.
- 5. Few advantages are ● Reduces programming effort by providing data structures and algorithms so you don't have to write them yourself. ● Increases performance by providing high-performance implementations of data structures and algorithms. Because the various implementations of each interface are interchangeable, programs can be tuned by switching implementations. ● Reduces the effort required to learn APIs by requiring you to learn multiple ad hoc collection APIs. ● Reduces the effort required to design and implement APIs by not requiring you to produce ad hoc collections APIs. ● Fosters software reuse by providing a standard interface for collections and algorithms with which to manipulate them.
- 6. The collection framework internally uses generics. Let’s code to understand the basics. Tip Open up a text editor ( gedit, Notepad ) and start typing hello world program in java
- 7. 2. Examples Hit the url : https://github.com/Pradhan10/Java-Collections-and-Generics ➔ The difference between storing data in array vs arraylist ? Start with drawing analogies to array in C. ➔ How are we printing all elements in arraylist ? Did we write the for loop to iterate all elements in list anywhere ?
- 8. Meet Joshua Bloch He wrote most of the java Collection framework and was chief architect in development of language.
- 9. Story for illustration purposes only The main interfaces of the Java Collections Framework
- 10. Why do you think the map interface was implemented seperately ? Tip Look at the mathematical difference between a set, a sequence and a mapping.
- 11. Code example two Hit the url : https://github.com/Pradhan10/Java-Collections-a nd-Generics/blob/master/QueueClass.java
- 12. Code example three Hit url : https://goo.gl/Md1 QAi
- 13. Generics
- 14. The main reasons for using generics : 1 : Type safety 2 : Cast iron guarantee
- 16. Cast-iron guarantee The implicit casts added by the compilation of generics never fail. (applies only when no unchecked warnings have been issued by the compiler.)
- 18. The 3 most used type parameters 1 : <E>, <T>, <K, V> (Used in Map interface) 2 : ? extends E (Used in iterator class) 3 : ? super T (Used in Comparator method)
- 19. Wildcard capture (?), add members of collection that are subtype of E
- 20. Wildcard capture (?), destination may have elements of any subtype of T
- 22. DSC Mail : [email protected] LinkedIn : https://www.linkedin.com /in/pradhan-rishi-sharma1 0
- 23. Thank you !