2. HowTo
3. Java Howtos

Java String

• Perform String to String Array Conversion in Java
• Remove Substring From String in Java
• Convert Byte Array in Hex String in Java
• Convert Java String Into Byte
• Generate Random String in Java
• The Swap Method in Java
• Get character in string by index in Java
• Trim a string in Java
• Convert String to ArrayList in Java
• Get the First Character of a String in Java
• Return a String in Java
• Comparison Between string.equals() vs == in Java
• Convert Double to String in Java
• Sort a String Array Alphabetically in Java
• Copy a String in Java
• Syllable Counter in Java
• Convert String Array Into Int Array in Java
• Compare Strings Alphabetically in Java
• Convert String to Hex in Java
• Find All Permutations of a Given String in Java
• Write Strings to CSV File in Java
• Currency Format in Java
• Convert an Array to String in Java
• Convert String to Int Array in Java
• Save a String to a File in Java
• Get Word Count of a String in Java
• Parse a String in Java
• Convert Float to String and String to Float in Java
• Convert Object to String in Java
• Print New Line in Java
• Split a String by Space in Java
• Concatenate Strings in Java
• Escape Characters in Java
• Boolean to String in Java
• Count Characters in a String in Java
• Enum to String in Java
• Iterate Over Characters of String in Java
• Replace Character in String in Java
• Replace Multiple Characters in String in Java
• String to Boolean in Java
• Add Char to String in Java
• Convert Binary String to Int in Java
• Get the Last Character of a String in Java
• Print Quotation Marks in Java
• Replace Character in String at Index in Java
• Remove a Character From String in Java
• Do String Interpolation in Java
• Multiply Strings in Java
• Convert String to InputStream in Java
• Convert String to JSON Object in Java
• Convert an InputStream Into a String in Java
• Sort a String in Java
• Get the Length of a 2D Array in Java
• Split String to Array in Java
• Reverse a String in Java
• Check if a String Contains Character in Java
• Convert Byte Array to String in Java
• Convert String to Date in Java
• Capitalize the First Letter of a String in Java
• Convert an Arraylist to a String in Java
• Remove the Last Character From the String in Java
• Check if a String Is an Integer in Java
• Check if a String Is Empty or Null in Java
• Convert Date to String in Java
• Convert a String to an Int in Java
• Convert a Char to a String in Java
• Convert a String to Char in Java
• Convert a String to Long in Java
• Convert String Date to Timestamp in Java
• Remove Punctuation From String in Java
• Convert an Integer to a String in Java
• Remove Whitespace From String in Java
• Check Whether a String Contains a Substring in Java
• Convert String to Double in Java
• Read a File to a String in Java
• Check if a String Is a Number in Java
• Split a String in Java

Java ArrayList

• Sort Objects in ArrayList by Date in Java
• Convert List to ArrayList in Java
• Get ArrayList of int array in Java
• Shuffle Deck of Cards in Java
• Convert String to ArrayList in Java
• Get the Last Element from an ArrayList in Java
• Return an ArrayList in Java
• Nested ArrayList in Java
• Deep Copy ArrayList in Java
• Convert Int Array to Arraylist in Java
• Copy ArrayList in Java
• Initialize ArrayList in Java
• Print an ArrayList in Java
• Create a 2D ArrayList in Java
• Convert an Arraylist to a String in Java
• Create ArrayList From Array in Java

Java Sorting

• Sort Objects in ArrayList by Date in Java

Java Array

• Concatenate Two Arrays in Java
• Convert Byte Array in Hex String in Java
• Remove Duplicates From Array in Java
• The push() Function in Java
• Initialize an array in constructor in Java
• Shuffle Deck of Cards in Java
• Convert String to ArrayList in Java
• Create a Subarray in Java
• Shuffle Array in Java
• Array of Linked List in Java
• Return Two Values in Java Function
• Check an Array Contains a Particular Value in Java
• Increase an Array Size in Java
• Pass an Array to a Method in Java
• Sort a String Array Alphabetically in Java
• Create an Array of Objects in Java
• Array Range in Java
• Create Array of an Array in Java
• Create a Dynamic Array in Java
• Deep Copy an Array in Java
• Convert Byte Array to Integer in Java
• Convert String Array Into Int Array in Java
• Get the Sum of an Array in Java
• Initialize All Array Elements to Zero in Java
• Resize an Array While Keeping the Current Elements in Java
• Clear an Array in Java
• Generic Array Creation in Java
• Populate an Array in Java
• Find the Max Number in an Array in Java
• Add Integers to an Array
• Convert an Array to String in Java
• Remove Element From Array and Then Shift Other Elements in Java
• Shift an Array in Java
• Declare an Array in Java
• Convert String to Int Array in Java
• Empty Array in Java
• Convert Int Array to Arraylist in Java
• Initialize 2D Array in Java
• Copy Array in Java
• Java Array Indexof
• Return Array in Java
• Return Empty Array in Java
• Sort 2D Array in Java
• Swap Arrays in Java
• Check if an Array Contains Int in Java
• Convert Char Array to Int in Java
• Get Char Array's Length in Java
• Print 2D Array in Java
• Initialize an Empty Array in Java
• Print an Array in Java
• Get Length of Array in Java
• Convert List to Array in Java
• Initialize a String Array in Java
• Sort Array Elements in Java
• Reverse an Int Array in Java
• Create ArrayList From Array in Java
• Convert Integer List to Int Array in Java
• Convert an Array to a List in Java
• Check Whether an Array Is Null/Empty in Java
• Initialize an Array in Java
• Add New Elements to an Array in Java

Java Byte

• Convert Java String Into Byte
• Write byte to file in Java
• Convert Byte to Int in Java

Java DateTime

• Add One Day to a Date in Java
• Compare Two Dates in Java
• Get the Current Year in Java.
• Get Current TimeStamp in Java Date
• Get Year From Date in Java
• java.util.date to java.sql.date in Java
• Get Today's Date in Java
• Subtract Dates in Java
• Convert String to Timestamp in Java
• Convert String to DateTime Object in Java
• Get the Current Date-Time in Java
• Convert Date to String in Java
• Convert String Date to Timestamp in Java

Java Int

• Convert Int to Char in Java
• Convert Int to Double in Java
• Calculate Length of Integer in Java
• Convert Byte to Int in Java
• Calculate Power of Integers in Java
• Convert Double to Int in Java
• Convert Char Array to Int in Java
• Convert Binary String to Int in Java
• Java Convert Hex String to Int
• Check if a String Is an Integer in Java
• Convert Char to Int in Java
• Convert Long to Int in Java
• Convert Integer List to Int Array in Java
• Get the Separate Digits of an Int Number in Java
• Convert an Integer to a String in Java

Java Char

• Convert Int to Char in Java
• Represent empty char in Java
• Empty Character Literal in Java
• Char to Uppercase/Lowercase in Java
• Check if a Character Is Alphanumeric in Java
• Compare Characters in Java
• Generate Random Character in Java
• Get a Char From the Input in Java
• Count Characters in a String in Java
• Iterate Over Characters of String in Java
• Replace Character in String in Java
• Add Char to String in Java
• Get the Last Character of a String in Java
• Replace Character in String at Index in Java
• Remove a Character From String in Java
• Convert an ASCII Code to Char
• Convert Char to Int in Java
• Convert Character to ASCII Numeric Value in Java
• Convert a Char to a String in Java
• Convert a String to Char in Java

Java File

• Remove Line Breaks Form a File in Java
• Get the Count of Line of a File in Java
• Open a file in Java
• Write byte to file in Java
• Append Text to a Text File in Java
• Read a Text File in Java
• Rename a File in Java
• Save a String to a File in Java
• How to Read XML File in Java
• Check if a File Exists in Java
• Get the File Extension of a File in Java
• Get the Current Working Directory in Java
• Read All Files of a Folder in Java
• Convert File to a Byte Array in Java
• Read a Large Text File Line by Line in Java
• Create a File and Write Data to It in Java
• Read a File to a String in Java

Java Double

• Convert Int to Double in Java
• Float and Double Data Type in Java
• Convert Double to String in Java
• Convert Double to Float in Java
• Truncate Double in Java
• Format Double Value in Java
• Convert Double to Int in Java
• Round a Double to Two Decimal Places in Java
• Convert String to Double in Java

Java Media

• Play Sound in Java

Java Function

• Return a Boolean Method in Java
• Return Two Values in Java Function
• Java Optional Parameters
• Pass a Function as a Parameter in Java

Java Queue

• Enqueue and Dequeue in Java
• PriorityQueue in Java
• Queue offer vs add in Java
• FIFO Queue in Java
• Instantiate Queue in Java

Java Threading

• Mutex in Java

Java Random

• Set Random Seed in Java
• Generate Random Double Values Between 0 and 1 in Java

Java Scanner

• Difference Between next() and nextLine() Methods From Java Scanner Class
• Get a Keyboard Input in Java
• Press Enter to Continue in Java
• Get a Char From the Input in Java
• Clear Scanner in Java
• Close a Scanner in Java

Java JSON

• Convert JSON Strings to Java Objects
• Convert XML to JSON in Java
• Read JSON File in Java
• Parse JSON in Java
• Convert String to JSON Object in Java
• Convert JSON to Map in Java
• Convert Hashmap to JSON Object in Java

Java Object

• Convert JSON Strings to Java Objects
• Print Objects in Java
• Instantiate an Object in Java
• Create an Array of Objects in Java
• Clone an Object in Java
• Get Type of Object in Java
• Convert Object to String in Java
• Check if an Object Is Null in Java
• Delete an Object in Java

Java XML

• Convert XML to JSON in Java

Java Math

• Double Division in Java
• Calculate Average in Java
• Pi Constant in Java
• Fractions in Java
• Modulus in Java
• Recursive Fibonacci Sequence in Java
• Calculate Power of Integers in Java
• Generate Random Number Within a Specified Range in Java
• Infinity in Java
• Do Power in Java

Java string

• Check empty string in Java

Java Integer

• Convert int to integer in Java
• Long.MAX_VALUE in Java
• Convert Int to Float in Java
• Create Unsigned Int in Java
• Difference Between Long and Int Data Types in Java
• Convert Boolean to Int in Java
• Check if Input Is Integer in Java
• Integer Division in Java
• Compare two integers in Java
• Convert a String to an Int in Java

Java char

• The char equals Method in Java

Java Class

• What is a driver class in Java
• Set classpath in Java
• Private Static Variable in Java
• Super in Java
• Get class name in Java
• Extend Two Classes in Java
• Access a Variable From Another Class in Java
• Static Class in Java
• Import Custom Class in Java
• Call a Variable From Another Method in Java

Java List

• Convert List to ArrayList in Java
• Sort Linked List in Java
• Create a Concurrent List in Java
• Sort a List in Java
• Concatenate List in Java
• Iterate Through a Linked List in Java
• Iterate Through List in Java
• Initialize List of String in Java
• Print List in Java
• Convert Integer List to Int Array in Java
• Convert an Array to a List in Java
• Join Two Lists in Java
• Create a New List in Java

Java Accessor

• Accessor Methods in Java

Java GUI

• Get Value From JTextField
• Create a Dropdown Menu in Java
• Message Box in Java
• Draw a Line in Java
• Create Pop Window in Java
• Draw a Circle in Java
• Draw a Triangle in Java

Java Interface

• Implement multiple interfaces in Java
• Difference between an Interface and an Abstract class in Java

Java JAR

• Make a Java File Executable

Java Stack

• Print Stack in Java

Java Bean

• What is Java Bean

Java Map

• Create map in Java
• Create an Ordered Map in Java
• Difference between hashmap and map in Java
• Sort a Map by Value in Java
• Get Key From Value in Java Hashmap
• Convert JSON to Map in Java
• Iterate Over Each Element of Map in Java

Java Operator

• Java typeof Operator
• The arrow operator -> in Java
• The XOR Operator in Java
• Difference Between & and && in Java
• Difference Between i++ and ++i Operators in Java
• Question Mark and Colon in Java

Java Obfuscation

• Code obfuscation in Java

Abstract Class

• Difference between an Interface and an Abstract class in Java

Java Print

• Java system.out.println() Method
• Print a table in Java
• Print New Line in Java

Java KeyListener

• Use KeyListener in Java

Java JLabel

• Display an image in Java

Java Image

• Display an image in Java
• Rotate an image in Java
• Resize an Image in Java

Java Graphics

• Draw a 2D Rectangle in Java

Java Float

• Float and Double Data Type in Java
• Convert Int to Float in Java
• Convert Double to Float in Java
• Convert Float to String and String to Float in Java
• Print a Float With 2 Decimal Places in Java

Java Heap

• Implement min-heap in Java
• Implement Min-Max Heap in Java

Java Tree

• Implement tree in Java

Java Binary Tree

• Implement tree in Java

Java ElapsedTime

• Make a Stopwatch in Java

Java Audio

• Play mp3 in Java

Java Method

• Return multiple values in Java
• The Difference Between Static and Dynamic Binding in Java
• Use Static Methods in Java
• Pass an Array to a Method in Java
• Pass a Method as a Parameter in Java
• Exit a Method in Java
• Java Default Parameters
• args parameter in Java
• Call a Variable From Another Method in Java
• Call a Method in Another Class in Java

Java Printf

• Use Printwriter in Java

Java HashMap

• Collision in Hashmap in Java
• HashMap, HashSet and Hashtable in Java
• Sort a HashMap by Key in Java
• Sort HashMap in Java
• Difference between hashmap and map in Java
• Difference between hashtable and hashmap in Java
• Update Value in Hashmap in Java
• Iterate Through HashMap in Java
• Get Keys From HashMap in Java
• Print HashMap in Java

Java Boolean

• Initialise Boolean Variable in Java
• Convert Boolean to Int in Java
• Boolean to String in Java
• String to Boolean in Java

Java Loop

• Shuffle Deck of Cards in Java
• Break Nested Loops in Java
• Exit a While Loop in Java
• Java for Loop With Two Variables

Java JavaFX

• Add a Background Image in JavaFX

Java Home

• Get the User Home Directory in Java

Java Directory

• Get the User Home Directory in Java
• Create Directory in Java

Java Constructor

• Overload a Constructor in Java
• The Default Constructor in Java
• Call Another Constructor in Java

Java Length

• The Difference Between Size and Length in Java

Java Size

• The Difference Between Size and Length in Java

Java Annotation

• Annotation @param in Java
• Annotation Symbol @ in Java

Java Email

• Email Validation in Java

Java Comment

• Java Block Comments

Java Linked List

• Print Linked List in Java
• Array of Linked List in Java
• Sort Linked List in Java
• Doubly Linked List in Java

Java Break

• The break Statement in Java

Java Sort

• Create an Ordered Map in Java
• Sort Comparator in Java

Java FIFO

• FIFO Queue in Java

Java Installation

• Install Java in Ubuntu
• Install Java in macOS

Java Javac

• Add Javac to Path in Windows 10
• Set Java_home in Linux

Java IO

• Append Text to a Text File in Java
• Relative Path in Java
• Convert Inputstream to Byte Array in Java
• Convert an InputStream Into a String in Java
• Get the File Extension of a File in Java
• Read All Files of a Folder in Java

Java Variable

• Increase an Array Size in Java
• Access a Variable From Another Class in Java
• Create Global Variable in Java
• Initialize Multiple Variables in Java

Java Scheduling

• Java Scheduling

Java Logging

• Use a Logger in Java

Java Long

• Difference Between Long and Int Data Types in Java
• Convert a String to Long in Java

Java Comparable

• Comparable vs Comparator in Java

Java Comparator

• Comparable vs Comparator in Java
• Sort Comparator in Java

Concurrent List

• Create a Concurrent List in Java

Java Destructor

• Destructor in Java

Java HashSet

• HashMap, HashSet and Hashtable in Java

Java Hashtable

• HashMap, HashSet and Hashtable in Java
• Difference between hashtable and hashmap in Java

Java Logic

• Or Statement in Java
• Define and Use || in Java
• Java or/and Logic

Java Set

• Sort a Set in Java
• Find a Set Intersection in Java
• Iterate Through Set in Java

Java Struct

• Struct in Java

Java Exception

• Throw Multiple Exception in Java
• What Is a Null Pointer Exception in Java
• Catch Multiple Exceptions in Java

Java Override

• Override equals() in Java
• Override the toString Method in Java

Char Array

• Declare a Char Array in Java

Java URLEncoder

• Encode a URL in Java

Java Time

• CET Time in Java

Java Histogram

• Histogram Program in Java

Java Color

• Set Color in Java

Java Database

• Connect a MySQL Database in Java

Java Input

• Get a Keyboard Input in Java
• Java Wait for Input
• Input Validation in Java
• Get User Input in Java

Java Timer

• Make a Countdown Timer in Java
• Java Timer

Java ArrayList, Java Object

• Add an Object in an Arraylist in Java

Java Hex

• Convert String to Hex in Java
• Java Convert Hex String to Int

Java Keyword

• The assert Keyword in Java

Java CSV

• Write Strings to CSV File in Java
• Parse CSV in Java

Java Date

• Java Change Date Format

Java UML

• UML Transform in Java

Java Constant

• Java Constant

Java Download

• Download File in Java

Java JRE

• Download Java Runtime Environment

Java Location

• Find Java Location in Windows

Java Decompiler

• Java Decompiler

Java Environment

• Java Environment Variables

Java Array Shift

• Remove Element From Array and Then Shift Other Elements in Java

Java Jar

• Java to Exe

Java Encryption

• Encrypt Password in Configuration Files in Java

Java GUID

• Create GUID in Java

Java Statement

• Java One Line if Statement

Java Thread

• Daemon Thread in Java
• Get Thread Id in Java
• Kill Thread in Java

Java Collection

• Implement Key Value Pair in Java
• Iterate Over Each Element of Map in Java

Java Scope

• Create Global Variable in Java

Java Number

• Generate Random Number Within a Specified Range in Java
• Round Up A Number in Java
• Generate a Random Number Between 1 and 10 in Java

Java Path

• Relative Path in Java

Java Algorithm

• Java Binary Search Interactive and Recursive
• Java Binary Search

Java AWT

• Draw a Triangle in Java

Java Switch

• Switch on Enum in Java

Java Enum

• Switch on Enum in Java
• Enum to String in Java

java Arraylist

• Initialize List of String in Java

Java InputStream

• Convert String to InputStream in Java

Java Console

• Clear the Console in Java
• Get Input From the Console in Java

Java ASCII

• Convert an ASCII Code to Char
• Convert Character to ASCII Numeric Value in Java

Java Multithreading

• Delay Few Seconds in Java

Java Data Type

• Check Type of a Variable in Java

Java Hashmap

• Get Key From Value in Java Hashmap
• Convert Hashmap to JSON Object in Java