{"id":15409,"date":"2020-12-10T01:34:22","date_gmt":"2020-12-10T01:34:22","guid":{"rendered":"https:\/\/demo.edublink.co\/?p=15409"},"modified":"2024-07-23T08:34:14","modified_gmt":"2024-07-23T08:34:14","slug":"crafting-effective-learning-paths-at-curriculum-corner","status":"publish","type":"post","link":"https:\/\/cnsfly.com\/vytcdc\/crafting-effective-learning-paths-at-curriculum-corner\/","title":{"rendered":"Collections Data-structure in Java"},"content":{"rendered":"

Any group of individual objects which are represented as a single unit is known as the collection of the objects. In Java, a separate framework named the \u201cCollection Framework\u201d has been defined in JDK 1.2 which holds all the collection classes and interface in it.<\/p>\n

The Collection interface (java.util.Collection) and Map interface (java.util.Map) are the two main \u201croot\u201d interfaces of Java collection classes.<\/p>\n

\/\/import util package[all classes]\r\nimport java.util.*;\r\npublic class StartCode {\r\n    public static void main(String[] args) {\r\n        System.out.println(\"Welcome to code java collection framework\");\r\n       \/*\r\n       creating collection\r\n       1)Type Safe- same type of elements(objects) are added to collection\r\n       2)Un Type safe- different types of elements can be added to collection\r\n        *\/\r\n        \/\/Type safe collection\r\n        ArrayList<String> names = new ArrayList<String>();\r\n        names.add(\"Abdul\");\r\n        names.add(\"Sitara\");\r\n        names.add(\"Roshni\");\r\n        names.add(\"Vandna\");\r\n        names.add(\"Vandna\");\r\n        System.out.println(names);\r\n        \/\/get\r\n\/\/        System.out.println(names.get(0));\r\n\/\/        System.out.println(names.get(1));\r\n        \/\/un type safe\r\n\/\/        LinkedList list = new LinkedList();\r\n\/\/        list.add(\"Sachin\");\r\n\/\/        list.add(101);\r\n\/\/        list.add(625.5124);\r\n\/\/        list.add(true);\r\n\/\/        System.out.println(list);\r\n        \/\/remove\r\n        names.remove(\"Roshni\");\r\n        System.out.println(names);\r\n        \/\/size\r\n        System.out.println(\"SIZE = \" + names.size());\r\n        \/\/check item is there or not\r\n        \/\/ Type ka equals method call karta hai checking karne ke lie\r\n        \/\/Student\r\n        System.out.println(names.contains(\"Durgesh Kumar\"));\r\n        \/\/check for empy\r\n        System.out.println(names.isEmpty());\r\n        \/\/setting value..\r\n        \/\/names.set(1,\"Ram\");\r\n        names.add(1, \"Ram\");\r\n        System.out.println(names);\r\n        \/\/remove all elements\r\n\/\/        names.clear();\r\n        System.out.println(names);\r\n        Vector<String> vector = new Vector<>();\r\n        vector.addAll(names);\r\n        System.out.println(\"VECTOR \" + vector);\r\n        System.out.println(\"_____________________________________\");\r\n        HashSet<Double> nms = new HashSet<>();\r\n        nms.add(14.14);\r\n        nms.add(34.12354);\r\n        nms.add((2354.235));\r\n        nms.add(99.3);\r\n        nms.add(99.3);\r\n        nms.add(5.3);\r\n        System.out.println(nms);\r\n        TreeSet<Double> tset = new TreeSet<>();\r\n        tset.addAll(nms);\r\n        System.out.println(tset);\r\n    }\r\n}<\/pre>\n
TraverseExample.java<\/h3>\n
import java.util.*;\r\nimport java.util.function.Consumer;\r\npublic class TraverseExample {\r\n    public static void main(String[] args) {\r\n        ArrayList<String> names = new ArrayList<String>();\r\n        names.add(\"Abdul\");\r\n        names.add(\"Sitara\");\r\n        names.add(\"Roshni\");\r\n        names.add(\"Vandna\");\r\n        names.add(\"Vandna\");\r\n        names.add(\"ABC\");\r\n        \/\/for each loop:\r\n        for(String str:names)\r\n        {\r\n            System.out.print(str +\"\\t\"+str.length()+\"\\t\");\r\n            StringBuffer br=new StringBuffer(str);\r\n            System.out.println(br.reverse());\r\n        }\r\n        System.out.println(\"________________________\");\r\n        \/\/traversing using ITERATOR: Forward traversing\r\n        Iterator<String> itr = names.iterator();\r\n        while(itr.hasNext())\r\n        {\r\n            String next = itr.next();\r\n            System.out.println(next);\r\n        }\r\n        System.out.println(\"+++++++++++++++++++++++\");\r\n\r\n        \/\/backward traversal of collection LISTITERATOR\r\n        ListIterator<String> litr = names.listIterator(names.size());\r\n        while(litr.hasPrevious())\r\n        {\r\n            String previous = litr.previous();\r\n            System.out.println(previous);\r\n        }\r\n        \/\/Enumeration\r\n        System.out.println(\"++++++++FOR EACH METHOD+++++++++++++\");\r\n        \/\/for each method\r\n        names.forEach(str->{\r\n            System.out.println(str);\r\n        });\r\n\r\n        System.out.println(\"SORTING OF ELEMENTS\");\r\n        TreeSet<String> set=new TreeSet<>();\r\n        set.addAll(names);\r\n        set.forEach(e->{\r\n            System.out.println(e);\r\n        });\r\n\/\/        Comparable\r\n\/\/        Comparator\r\n    }\r\n}<\/pre>\n
MapExample<\/b><\/h3>\n
import java.util.HashMap;\r\nimport java.util.function.BiConsumer;\r\n\r\npublic class MapExample {\r\n    public static void main(String[] args) {\r\n\r\n        HashMap<String,Integer>  courses=new HashMap<>();\r\n\r\n        \/\/adding elements\r\n        courses.put(\"Core Java\",4000);\r\n        courses.put(\"Basic Python\",3500);\r\n        courses.put(\"Spring\",8000);\r\n        courses.put(\"Android\",4000);\r\n        courses.put(\"Android\",6000);\r\n        courses.put(\"PHP\",2414);\r\n        System.out.println(courses);\r\n\/\/        courses.forEach((e1,e2)->{\r\n\/\/            System.out.println(e1+\"=>\"+e2);\r\n\/\/        });\r\n        courses.forEach((key,value)->{\r\n            System.out.print(key);\r\n            System.out.print(\"=>\");\r\n            System.out.println(value);\r\n            System.out.println();\r\n        });\r\n        \/\/entry set\r\n        \/\/key set\r\n        System.out.println(courses.get(\"Core Java\"));\r\n    }\r\n}<\/pre>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
Any group of individual objects which are represented as a single unit is known as the collection of the objects. In Java, a separate framework named the \u201cCollection Framework\u201d has<\/p>\n","protected":false},"author":1,"featured_media":15621,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[77],"tags":[25,26],"class_list":["post-15409","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java","tag-design","tag-development"],"_links":{"self":[{"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/posts\/15409","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/comments?post=15409"}],"version-history":[{"count":0,"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/posts\/15409\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/media\/15621"}],"wp:attachment":[{"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/media?parent=15409"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/categories?post=15409"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cnsfly.com\/vytcdc\/wp-json\/wp\/v2\/tags?post=15409"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}