How HashMap Works in Java ?<\/h2>\n

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• HashMap is one of the most widly used implementation of Map to store key-value pairs. To implement HashMap with ArrayList.<\/li>\n
• It is provides two basic HashMap functions they are: get(key) and put(key, value).<\/li>\n
• While storing code to be checking the duplicate values. While duplicate values are presents to be removed.<\/li>\n
• Implementation should not be used as a replacement of HashMap. Also while testing the code, make sure that the Object used in the KEY has proper implementation of equals() method.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n
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  Example:<\/h2>\n<\/div>\n<\/div>\n

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  package com.journaldev.util;import java.util.ArrayList;import java.util.List;public class MyHashMap {\tclass Container{\t\tObject key;\t\tObject value;\t\tpublic void insert(Object k, Object v){\t\t\tthis.key=k;\t\t\tthis.value=v;\t\t}\t}\t\tprivate Container c;\tprivate List<Container> recordList;\t\tpublic MyHashMap(){\t\t\t\tthis.recordList=new ArrayList<Container>();\t}\t\tpublic void put(Object k, Object v){\t\tthis.c=new Container();\t\tc.insert(k, v);\t\t\/\/check for the same key before adding\t\tfor(int i=0; i<recordList.size(); i++){\t\t\tContainer c1=recordList.get(i);\t\t\tif(c1.key.equals(k)){\t\t\t\t\/\/remove the existing object\t\t\t\trecordList.remove(i);\t\t\t\tbreak;\t\t\t}\t\t}\t\trecordList.add(c);\t}\t\tpublic Object get(Object k){\t\tfor(int i=0; i<this.recordList.size(); i++){\t\t\tContainer con = recordList.get(i);\t\t\t\/\/System.out.println("k.toString():"+k.toString()+"con.key.toString()"+con.key.toString());\t\t\tif (k.toString()==con.key.toString()) {\t\t\t\t\t\t\t\treturn con.value;\t\t\t}\t\t\t\t\t}\t\treturn null;\t}\t\tpublic static void main(String[] args) {\t\tMyHashMap hm = new MyHashMap();\t\thm.put("1", "1");\t\thm.put("2", "2");\t\thm.put("3", "3");\t\tSystem.out.println(hm.get("3"));\t\thm.put("3", "4");\t\t\t\tSystem.out.println(hm.get("1"));\t\tSystem.out.println(hm.get("3"));\t\tSystem.out.println(hm.get("8"));\t}}<\/code><\/pre> <\/div><\/figure>\n<\/div>\n<\/div>\n
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  3<\/span>\r\n1<\/span>\r\n4<\/span>\r\nnull<\/span><\/span><\/code><\/pre>\n<\/figure>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
  Answer : HashMap is one of the most widly used implementation of Map to store key-value pairs…<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"passster_activate_protection":false,"passster_protect_child_pages":"","passster_protection_type":"password","passster_password":"","passster_activate_overwrite_defaults":"","passster_headline":"","passster_instruction":"","passster_placeholder":"","passster_button":"","passster_id":"","passster_activate_misc_settings":"","passster_redirect_url":"","passster_hide":"no","passster_area_shortcode":"","gtb_hide_title":false,"gtb_wrap_title":false,"gtb_class_title":"","gtb_remove_headerfooter":false,"footnotes":""},"categories":[4004],"tags":[195,491,360,203,199,214,198,363,209,4121,15937,205,2936,222,4118,4111,4120,4122,4113,4112,4115,4119,4123,196,4116,4117,212,213,286,207,366,204,217,282,4023,483,206,200,197,280,364,4114,968,4124],"class_list":["post-629","post","type-post","status-publish","format-standard","hentry","category-java","tag-accenture-interview-questions-and-answers","tag-applied-materials-interview-questions-and-answers","tag-atos-interview-questions-and-answers","tag-capgemini-interview-questions-and-answers","tag-casting-networks-india-pvt-limited-interview-questions-and-answers","tag-cgi-group-inc-interview-questions-and-answers","tag-chetu-interview-questions-and-answers","tag-ciena-corporation-interview-questions-and-answers","tag-collabera-technologies-interview-questions-and-answers","tag-custom-hashmap-implementation-in-java","tag-dark-horse-digital-interview-questions-and-answers","tag-dell-international-services-india-pvt-ltd-interview-questions-and-answers","tag-fis-global-business-solutions-india-pvt-ltd-interview-questions-and-answers","tag-flipkart-interview-questions-and-answers","tag-hashmap-internal-implementation-analysis-in-java","tag-hashmap-internal-working","tag-hashmap-iterator-implementation","tag-hashmap-java","tag-hashset-vs-hashmap","tag-how-hashmap-works-internally","tag-how-hashmap-works-internally-in-java","tag-how-hashmap-works-internally-in-java-with-example","tag-how-hashtable-works-internally-in-java","tag-ibm-interview-questions-and-answers","tag-implement-hashmap-in-java-interview","tag-implement-hashmap-without-using-collections","tag-indecomm-global-services-interview-questions-and-answers","tag-infosys-technologies-interview-questions-and-answers","tag-lt-infotech-interview-questions-and-answers","tag-mphasis-interview-questions-and-answers","tag-netapp-interview-questions-and-answers","tag-oracle-corporation-interview-questions-and-answers","tag-peoplestrong-interview-questions-and-answers","tag-persistent-systems-interview-questions-and-answers","tag-rbs-india-de-interview-questions-and-answers","tag-reliance-industries-ltd-interview-questions-and-answers","tag-sap-labs-india-pvt-ltd-interview-questions-and-answers","tag-tech-mahindra-interview-questions-and-answers","tag-unitedhealth-group-interview-questions-and-answers","tag-virtusa-consulting-services-pvt-ltd-interview-questions-and-answers","tag-wells-fargo-interview-questions-and-answers","tag-what-is-hashmap","tag-wipro-infotech-interview-questions-and-answers","tag-write-your-own-hashmap-hashtable-implementation-in-java"],"yoast_head":"\n