Core java

In this post, we will see how to split a String by delimiter in java. Sometimes, we need to split a String by delimiter for example: while reading a csv file, we need to split string by comma(,). We will use String class’s split method to split a String. This split(regex)  takes a regex as […]

There are multiple ways to convert Char Array to String in java. Some of them are: Using String class’s constructor (By passing Char array to contructor) Using String class’s valueOf method Using iterating char array Example: [crayon-6629a581cddb5363799583/] When you run above program, you will get below output [crayon-6629a581cddbe590535780/] Other String Programs are : How to […]

Java String’s toCharArray() method can be used to convert String to char Array in java. It is simplest method to convert String to char Array. Example: [crayon-6629a581ce531762070203/] When you run above program, you will get below output: [crayon-6629a581ce539710325477/] Other String Programs are : String : How to reverse String in java How to check if […]

HashMap does not preserve order of element but what if you want to sort it by keys or values. In this post, we will see how to sort HashMap by keys or values. Java HashMap tutorial: HashMap in java HashMap internal working hash and indexfor method in HashMap hashcode and equals in java sort HashMap […]

In this post, we will see about LinkedHashSet in java. LinkedHashSet is same as HashSet except that it maintains insertion order. Some points about LinkedHashSet LinkedHashSet implements Set interface and extends HashSet class. LinkedHashSet maintains insertion order, so when you will be able to access elements in the order they were inserted like ArrayList. Example: LinkedHashSetMain.java [crayon-6629a581cf40b629478866/] When you run […]

HashMap is hash table based implementation of Map interface. It stores entry in key-value pairs. It maps keys to values. It is one of the most used Collection. Java HashMap HashMap implements Map an interface that maps a key to value. It is not synchronized and is not thread-safe. Duplicate keys are not allowed One […]

TreeMap class implements Map similar to HashMap. Some important points about TreeMap: TreeMap implements Map interface and extends HashMap class. TreeMap is implemented using Red black tree based NavigableMap. TreeMap is ordered collection and store its elements in natural ordering of keys. Key which you would like to put in TreeMap must implement Comaparable interface or you can […]

LinkedHashMap is a Hashtable and linked list-based implementation of Map interface, with predictable insertion order. It maintains double linked list of all its entries, that’s how it differs from HashMap. Java LinkedHashMap Some points about LinkedHashMap LinkedHashMap implements Map interface and extends HashMap class. LinkedHashMap maintains insertion order, so when you will be able to […]

In this post, we will see how to calculate difference between two dates. Sometimes we have requirement to find no. of days between two dates or no. of hours between two dates. Java Program: [crayon-6629a581d18fd800422420/] When you run above program, you will get following output: [crayon-6629a581d1904997757563/]