Hashmap Archives • Crunchify

Hashmap • Tag Archive

Interview questions on Java HashMap, Data structure, etc are the most common and fundamental concepts. On Crunchify, we do have more than hundreds of tutorials for you to use free of charge.

How to Sort a HashMap by Key and Value in Java 8 – Complete Tutorial

May 1, 2022 by App Shah 2

In Java 8 – How to sort a Map? On Crunchify we have written almost ~400 java tutorials and this one is an addition to Java8 category. I love Java collection and have multiple tutorials on How to …

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Java Hashmap – containsKey(Object key) and containsValue(Object value) – Check if Key/Value Exists in Map

Apr 17, 2022 by App Shah

There are few concepts and technologies which comes by default with each and every programing language and Collection is one of them. Java Collection is a very big field. It comes …

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How to use net.jodah.ExpiringMap Maven Java Utility to Remove Expired Objects from HashMap Automatically?

Apr 12, 2022 by App Shah

Java without Java Collection is really hard to imagine. I spend almost couple of hours a day working on Java Projects for my clients. HashMap, Map, Static Objects, Java Interface are the …

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In Java how to Initialize HashMap? 7 different ways

Nov 16, 2021 by App Shah

In Java How to initialize HashMap? How to directly initialize a HashMap (in a literal way). There are 7 different ways you can initialize HashMap in Java. Method-1: Simple Mutable map: It's …

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In Java What is a Difference Between IdentityHashMap and HashMap + Performance Comparison

Oct 25, 2021 by App Shah 2

Sometime back I have a special case in which I have to compare Map's Key based on equality operator (==). The equality operator (==) compares the references (addresses in memory) of the two …

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How to Remove expired elements from HashMap and Add more elements at the Same Time – Java Timer, TimerTask and futures() – Complete Example

Jun 28, 2021 by App Shah

Hashmap, ArrayList, Static Map, Vectors, etc are the most used Java collection framework elements. There are infinite number of scenarios you could use this as per your need. This example is very …

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How to convert HashMap to ArrayList in Java?

Jul 18, 2020 by App Shah 4

Here is a simple example on how to convert HashMap to ArrayList in Java. Java Example: package com.crunchify; /** * @author Crunchify.com */ import java.util.ArrayList; import …

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Java: How to find Unique Values in ArrayList (using TreeSet, HashSet)

Jan 31, 2021 by App Shah 5

This tutorial gives you simple way to find unique values in ArrayList using TreeSet and HashSet. HashSet is much faster than TreeSet (constant-time versus log-time for most operations like add, remove …

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Java: How to Get Random Key-Value Element From HashMap

Oct 26, 2019 by App Shah 2

Is there a way to get the value of a HashMap randomly in Java? Of Course, below is a simple Java Code which represents the same. Also, at the end of program there is a bonus code to Shuffle …

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