Java Tutorial Index

Java Tutorial Java Features C++ vs Java Java History Java Hello World Java Development Kit Java Runtime Environment Java Virtual Machine Difference between JDK, JRE, and JVM Memory Areas in Java Java Operators Java Keywords Primitive Data Types Variables

Java Loops

Java Do While Loop Java While Loop Java For Loop Java Enhanced For Loop

Java Programs

Java Basic Programs Factorial Program in Java Fibonacci Series Program in Java Prime Number Program in Java Palindrome Number Program in Java Armstrong Number Program in Java Anagram Program in Java Pattern Programs in Java Calculator Program in Java Leap Year Program in Java Addition Program in Java Number Pattern Programs in Java Star Pattern Programs in Java Package Program in Java Pyramid Program in Java Sorting Program in Java String Palindrome Program in Java Even Odd Program in Java For Loop Program in Java If Else Program in Java Switch Case Program in Java GCD Program in Java LCM Program in Java Hello Program in Java Matrix Program in Java Menu Driven Program in Java Series Program in Java Client Server Program in Java Swapping Program in Java Pig Latin Program in Java Tower of Hanoi Program in Java Recursion Program in Java Matrix Multiplication Program in Java Perfect Number Program in Java Classes and Objects in Java Example Programs String Programs in Java Array Programs in Java Constructor Program in Java Inheritance Program in Java Abstract class Program in Java Interface Program in Java Encapsulation Program in Java Polymorphism Program in Java Exception Handling Program in Java Multithreading Program in Java Thread Program in Java Collection Programs in Java ArrayList Program in Java Stack Program in Java Applet Program in Java Swing Program in Java JDBC Program in Java Program to find and replace characters on string in java Program to find the duplicate characters in a string Program to check whether a given character is present in a string or not Java Program to Print Permutations of String Java program to find frequency of characters in a string Java Program to remove duplicate characters in a string Java Program to Sort an Array of 0's, 1's, and 2’s | Dutch National Flag Problem in Java Java Program to print even and odd numbers using 2 threads Java Program to generate binary numbers Java program to count the occurrences of each character Java Program to Add Digits Until the Number Becomes a Single Digit Number Program to Implement FLAMES Game in Java Packages Program in java Pangram Program in Java Java program to print matrix in Z form CRC Program in Java Star Program in Java Structure of Java Program RMI program in Java Caesar Cipher Program in Java Java Programming certification Round Robin Scheduling Program in Java Java Program to find the smallest element in a tree Program to Find Square Root of a Number Without sqrt Method in Java Program to Find the Common Elements between two Arrays in Java Automorphic Number Program in Java

Java Sorting

Sorting Algorithms in Java Merge Sort in Java Quick Sort in Java Bubble Sort in Java Insertion Sort in Java Selection Sort in Java Heap Sort in Java Radix Sort in Java Topological Sort in Java Bucket Sort in Java Counting Sort in Java Java Program to Create Set of Pairs Using HashSet

Java OOPs Concepts

OOPs - Object Oriented Programming Objects and Classes in Java Methods in Java Java Naming Conventions Constructors in Java Java this keyword Java static keyword Inheritance in Java Aggregation in Java Java super keyword Constructor Chaining and Constructor Overloading Java Polymorphism Static and Dynamic Binding in Java Java Abstraction Abstract class in Java Interface in Java Difference between Abstract class and Interface Java final keyword Packages in Java Access Modifiers in Java Java Wrapper classes Java Numbers Java Characters Java Integer Java Boolean Java Arrays Java Command Line Arguments Java strictfp Keyword Java Enumeration Java Math

Java Strings

Java Strings Java String Methods StringBuilder in Java StringBuffer in Java Java Regular Expressions StringBuffer vs StringBuilder String vs StringBuffer String vs StringBuilder String Manipulation in Java Java String Concatenation How to Reverse a String in Java String Array in Java How to Compare Two Strings in Java How to Concatenate Two Strings in Java Why String in Immutable in Java java.lang.NumberFormatException for Input String String Pool in Java Java Generate Random String How to take String Input in Java Java String Interview Questions

Java Exceptions

Exception Handling in Java Java try catch Java throw Java throws Difference between throw and throws Java finally Java Custom Exception Java Exception Propagation

Garbage Collection

Automatic Resource Management in Java Java Garbage Collection Java finalize() Java gc() Difference between final, finally and finalize Java Garbage Collection Interview Questions

Multithreading

Multithreading in Java Process and Thread in Java Basic Terms in Multithreading Java Thread creation Thread Scheduler in Java Java Thread class DeadLock in Java

Java IO

Java IO Java Read File Java file Reader Java Buffer Reader Java file Writer Java BufferedWriter Java InputStreamReader Scanner in Java Java StringReader Java StringReader Class Java StringWriter Class Java PrintWriter Java File Java Read File Line By Line Java FileInputStream Java FileOutputStream Java Create File Java Delete File Java Open File Java Read File to String Java copy file Jar File in Java Java FileNotFoundException

Serialization

Java Serialization Java transient

Networking

Java Network Programming Java Socket Programming Java URL Java URLConnection HttpURLConnection in Java Java InetAddress Java DatagramSocket and Java DatagramPacket

AWT

Java AWT

Swing

Swing in Java

Java Collections

Collections in Java Java List Interface ArrayList in Java LinkedList in Java Vector in Java Stack in Java ArrayList vs LinkedList in Java ArrayList vs Vector in Java Java Set Interface HashSet in Java LinkedHashSet in Java TreeSet in Java Java Queue Interface PriorityQueue in Java Deque in Java ArrayDeque in Java Java Map Interface HashMap in Java LinkedHashMap in Java TreeMap in Java Dictionary in Java Hashtable in Java Properties in Java Collections class in Java Java Comparable Java Comparator Comparable vs Comparator in Java

Java Generics

Generics in Java

Java Annotations

Annotations in Java

Java JDBC

Java JDBC Tutorial JDBC Architecture Types of JDBC Drivers JDBC vs ODBC Java Database Connectivity with MySQL Java Database Connectivity with Oracle Statements in java Prepared statement in Java Resultset in java Java ResultSetMetaData DatabaseMetaData in Java Callable Statement in Java Transaction Management in Java Design of JDBC

Java Differences

Java vs DotNET Java vs JavaScript Kotlin vs Java Java vs C++ C# vs Java Java float vs double Java vs Scala Java vs Go Java vs Golang Java Extends vs Implements Java vs Node.js Static vs Non-static in Java int vs Integer in Java Java protected vs private Java vs Dot Net Stack vs Heap in Java Java Array vs ArrayList Java SE vs EE Class vs Object in Java Java vs Bedrock Difference between = = and equals ( ) in java Difference between C, C++, java HashMap Vs HashTable Checked vs Unchecked Exceptions in Java Difference between print() and println() in Java Differences between Lock and Monitor in Java Concurrency Differences between Set and List in Java Char and String differences in Java Difference between String, StringBuffer and StringBuilder in java Difference between String and Char Array in Java Differences between Byte Code and Machine Code Difference between String Tokenizer and split Method in Java Difference between JIT and JVM in Java Difference Between Data Hiding and Abstraction in Java Difference Between BufferedReader and FileReader Difference Between Thread.start() and Thread.run() Difference between Aggregation and Composition in Java Difference between Constructor and Method in Java Difference between next() and nextline() in Java Difference between Static and Instance Methods in Java Differences and Similarities between HashSet, LinkedHashSet and TreeSet in Java Different Ways to Print Exception Message in Java Different Ways to Take Input from User in Java Difference Between Access Specifiers and Modifiers in Java Difference Between Java and PHP Difference Between replace() and replaceall() in Java Difference between this and super in Java Generics vs Wildcard in Java

How to

How to convert String to String array in Java How to find length of integer in Java How to get Day Name from Date in Java How to open the Java control panel How to resolve Illegal state exceptions in Java How to reverse a linked list in java How to encrypt password in Java How to calculate time complexity of any program in Java How to check version of java in Linux How to enable java in chrome How to run Java program How to set path in Java How to check the Java version in cmd How to install Java in Windows 10 How to run Java program in cmd How to add double quotes in a string in Java How to convert list to String in Java How to call a method in Java How to Set Environment Variables for Java How to sort an array in Java How to Create Immutable Classes in Java How to iterate HashMap in Java How to write Java program How to create an array in Java How to create a package in Java How to generate random numbers in Java How to input String in Java How to Create Singleton Class in Java How to sort a string in Java How to use scanner in Java How to achieve multiple inheritance in Java How to find the length of an Array in Java How to Read Java JSON file How to run Java program in Eclipse How to call a function in Java How to create array of objects in Java How to import packages in Java How to run applet Program in Java How to take Array Input in Java How to call static method in Java How to compare characters in Java How to compare dates in Java How to create a linked list in Java How to download Eclipse for Java How to get ASCII value of char in Java How to get the current date and time in Java How to handle NullPointerException in Java How to initialize string array in Java How to Install Java on MAC How to run java program in ubuntu How to find characters with the maximum number of times in a string java How to Set Java_home in Linux How to Split the String in Java with Delimiter How to take Multiple String Input in Java using Scanner class How to uninstall the Java in Ubuntu How to Update Java How to add Elements in Array in Java How to avoid deadlock in java How to Split String by Comma in Java How to remove special characters from String in Java How to remove last character from String in Java How to Read XML Files in Java How to download and install Eclipse in Windows How to Create an API in Java How to Round Double Float up to Two Decimal Places in Java How to create a mirror image of a 2D array in Java How to set timer in Java How to make Java Projects How to Create Different Packages for Different Classes in Java How to run Java program in command prompt How to run Java program in Eclipse How to calculate time difference in Java How to stop execution after a certain time in Java How to check data type in Java How to Reduce Time Complexity in Java How to check if date is valid in Java How many ways to create object in Java How to add 4 Hours to the Current Date in Java How to add 4 Years to the Current Date in Java How to add 6 Months to the Current Date in Java How to add 24 Hours to Date in Java How to Assign Static Value to Date in Java How to check Date is Greater in Java How to check Date Null in Java How to check valid date in Java How to Iterate List in Java How to increment and decrement date using Java How to Create a Generic List in Java How to compare two dates in different format in Java How to compare three dates in Java How to override toString() method in Java

Java 8 Features

Java 8 Features Lambda Expressions in Java Functional Interface in Java Streams in Java Java Base64 Encoding and Decoding Type Annotations in Java Java Stringjoiner Class Parallel Arrays Sort in Java Bifunction in java 8 Java 8 filters list Java 8 Consumer Interface in Java

Java 9 Features

Java 9 Tutorial Java 9 Try With Resources Java 9 Interface Private Method

Java 12

What’s new in Java 12

Java 13

Java 13 New Features

Java 14

New Features of Java 14

Java 15

What’s New in Java 15

Java 16

Java 16

Java 17

What is new in Java 17

Java Math Methods

Math.abs() Math.acos() Math.addExact() Math.asin() Math.atan () Math.atan2() Math.cbrt() Math.ceil() Math.copysign() Math.cos() Math.cosh() Math.decrementExact() Math.exp() Math.expm1() Math.floor() Math.floorDiv() Math.floorMod() Math.fma() Math.getExponent() Math.hypot() Math.IEEEremainder() Math.incrementExact() Math.log() Math.log10() Math.log1p() Math.max() Math.min() Math.multiplyExact() Math.multiplyFull() Math.negateExact() Math.nextAfter() Math.nextDown() Math.nextUp() Math.pow() Math.random() Math.rint() Math.round() Math.scalb() Math.signum() Math.sin() Math.sinh() Math.sqrt() Math.subtractExact() Math.tan() Math.tanh() Math.toDegrees() Math.toIntExact() Math.toRadians() Math.ulp()

Java String Methods

toCharArray() copyValueOf() endsWith() equals() equalsIgnoreCase() format() getBytes() getChars() hashCode() indexOf() intern() isEmpty() join() lastIndexOf() length() replace() replaceAll() replaceFirst() split() startsWith() subSequence() substring() toLowerCase() toUpperCase() trim() valueOf()

Java Conversion

Java Convert String to int Java Convert int to String Java Convert String to long Java Convert long to String Java Convert String to float Java Convert float to String Java Convert String to double Java Convert double to String Java Convert String to Date Java Convert Date to String Java Convert String to Object Java Convert Object to String Java Convert String to char Java Convert char to String Java Convert int to long Java Convert long to int

Java Keywords

Reserved Keywords in Java Java Case Keyword Java Class Keyword Java Continue Keyword Java Default Keyword Java Double Keyword Java Else Keyword Java Enum Keyword Java Extends keyword Java Finally Keyword Java Char Keyword Contextual keywords in Java Java Break Keyword Volatile keyword in Java Java Boolean Keyword Java Byte Keyword The final Keyword in Java Java For Keyword Java Float Keyword Java Instanceof Keyword Java If Keyword Java Int Keyword Java Import Keyword Java Package Keyword Java Public Keyword Java Implements Keyword Java Private keyword Java Protected Keyword Java Short Keyword Java Long Keyword Java Interface Keyword Java Try Keyword Java New Keyword Java Return Keyword Java Null Keyword this keyword in Java

Java Questions

What are Array strings in Java What is String in Java? What is string in Java why it's immutable What is advance Java? What is interpreter in Java? What is anagram in Java? How Many Ways to Create Objects in Java How annotations work in Java What is Core Java Why to use Enum in Java

Misc

List all files in a Directory in Java Nonagonal number in Java Null Pointer Exception in Java Package naming convention in Java PriorityBlockingQueue Class in Java Race Condition in Java Repdigit Numbers in Java Rotate matrix by 90 degrees in Java Segment Tree in Java Sierpinski Number in Java Sort Dates in Java Thread Safety and How to Achieve it in Java Normal and Trace of a Matrix in Java Transient variable in Java Tribonacci series in Java Web Crawler in Java Zigzag Traversal of Binary Tree in Java Java Full Stack Java IO filenotfoundexception Java Output Formatting Java Plot Java Pop Java Set to List Java Switch string Java Thread Lifecycle: States and Stages Java Viva Questions and Answers Lazy Propagation in Segment Tree in Java Level order Traversal of a Binary Tree in Java Method chaining in Java Narcissistic Number in Java Java Try-Catch Block Java concurrency interview questions Java CountDownLatch Java Editors Java Font Example of Static import in Java Implementing Queue Using Array in Java Instanceof operator in Java Interchange Diagonal elements in Java Java Arrays Fill Convert list to array Java Convert milliseconds to date in Java Copy data/content from one file to another in java Creating a Jar file in Java Crown Pattern in Java Duodecimal in Java Finding middle node of a linked list in Java Group by in Java 8 Hollow Diamond Pattern in Java Java Boyer Moore Catalan number in Java Cosmic Superclass in Java Fall through in Java Figurate Number in Java Java Anon Proxy Java RMI Lazy loading in Java Magnanimous Number in java Shallow copy in Java String to JSON in Java Tetranacci Number in Java Vigesimal in Java Why main method is static in Java Add Time in Java Bellman Ford Algorithm in Java Best Java Libraries Blockchain in Java Blocking Queue in Java Example Bully Algorithm code in Java Convert JSON File to String in Java Determine the Upper Bound of a Two-Dimensional Array in Java Java.net.ConnectionException Java.net.SocketException Web Service Response Time Calculation in Java Functional Interfaces in Java Singleton class in Java Awesome explanation of Strings in Java Object class in Java Static class in Java All the important string methods in Java String Handling Method in Java Advantages and Disadvantages of Strings in Java Big Decimal class in Java Class definition in Java Replace character in string Java String Coding Interview Questions in Java String isnullorempty in Java String Matches in Java Trim Method in String Java Bean class in Java Libraries in Java Arithmetic Operations on String in Java Convert Char array to string in java Check whether Java is installed or not Jagged Array in Java Java ArraylistRemove() Time Complexity Java Swing Time Picker Zigzag Array in Java Array and String based questions in Java Array and String with Examples in Java Best Practices to use String Class in Java Java String Java String Inbuilt functions Java String Matches vs Contains Sum of digits in string in java Check the presence of Substring in a String in java Java import packages Interfaces and Classes in Strings in Java Maximum length of string in java Hidden classes in Java Class memory in Java public static void main string args meaning in java Reverse a String in Java String Concatenation in Java Buffer reader to read string in Java Split String into String Array in Java Reverse a String using Collections in Java Upcasting and Downcasting in Java String Declaration in Java Method Overloading In Java Java Solid Principles Java Architecture Binary Search Java Java Type Casting Java Pass-by-Reference Java Framework List Java Destructors Java Control Statements Java Byte Code Java Beans Java Identifiers Character Array in Java Java Applications Java Substring Java Session Non-primitive data types in Java Matrix Multiplication in Java JIT in Java Java Tokens Java Externalization Default Virtual Behaviour in C++ vs Java Why we use static in Java Session Tracking in Java Knapsack problem in Java Java Logo Java exception list Java Iterator Java instance variable Frugal number in Java Fork Join in Java Date time API in java Compile time vs Runtime in java Compare time in java AES 256 Encryption in Java Advanced Java skills User Defined Exception in Java Upcasting in Java Tree Implementation in Java Special Operators in Java Reentrant Lock in Java Perfect Number in Java Java logger Java LinkedList vs ArrayList File Operation in Java Constructor Overloading in Java Conditional operator in Java Concurrent Linked Deque in Java with Examples Command Class in Java Best Java IDE Association in Java Access specifiers in Java AbstractSet Class in Java Adapter class in Java Composition in Java Mutable and Immutable in Java Static() Function in Java Traverse through HashMap in Java Vectors in Java Creation of Multi Thread in java Compile-time Error in Java Java Get Time in UTC Java.sql.Time Format Thread Concept in Java Creation of Multi-Thread in Java Enterprise Java Beans POJO in Java Java Constant Collection Interfaces in Java with Examples Deadlock Prevention and avoidance in Java Java List Implementations Java Xml Parser Method Overriding in Java Virtual Function in Java Advanced Java Viva Questions Application of Array in Java Economical number in Java Iterate JSON array in Java Java callable example Java Command not found Java Date add Days Java File Extension Java Location Java Trim User Defined Custom Exceptions in Java Java array list remove time complexity Java.lang.Exception.NoRunnableMethods Java Map Example Java Obfuscator Java Pi Java Queue Java time local date Java Xmx Uses of Java Applet Life Cycle in Java Best Java Security Framework BigDecimal toString() in Java Jdoodle Java Literals in Java MVC in Java Powerful Number in Java Read the XLSX file in Java Relatively Prime in Java Root exception in java Accessors and Mutator in Java Bottom view of a binary tree in Java Convert List to String in Java Equidigital in Java IdentityHashMap in Java Java Clone Array Java LDAP Authentication Java List Node Java Password Generator Magic Square in Java Pancake Sorting in Java Practical Number in Java Sublime Number in Java Sudoku in Java Compare Two Times in Java Diffie Hellman Algorithm in Java Java calculate age Map of Map in Java Minimum XOR value pair in Java Palindrome Partitioning problem in Java Pernicious Number in Java Prime Points in Java Rectangular Numbers in Java Sleep Time in Java Types of Statements in Java Unicode System in Java Zig Zag star and Number Pattern in Java Balanced Prime Number in Java ConcurrentSkipListSet in Java Construct the Largest Number from the Given Array in Java CopyOnWriteArrayList in Java Cyclic Barrier in Java Dangling Else problem in Java Display Unique Rows in a Binary Matrix in Java Empty Statement in Java Factorial of a Large Number in Java Facts about null in Java Rehashing in Java Singleton Design Pattern in Java Zebra Puzzle Problem in Java XOR of Array Elements Except Itself in Java Types of Sockets in Java Thread Synchronization in Java Set Up the Environment in Java Method and Block Synchronization in Java Fibodiv Number in Java House Numbers in Java GCD of Different SubSequences in Java Hogben Numbers in Java Decagonal Numbers in Java Converting Roman to Integer Numerals in java Check if the given array is mirror inverse in Java Block Swap Algorithm for array rotation in Java Java Binary Tree Binary Strings Without Consecutive Ones in Java Beautiful Array in Java Balanced Parentheses in Java Arithmetic exception in Java Add numbers represented by Linked Lists in Java Two Decimal Places Java Intersection Point of two linked list in Java Find next greater number with same set of digits in Java Getter and Setter Method in Java Example Java Binary to Hexadecimal Java Calculate Average of List Iccanobif Numbers in Java Java delete directory Tug of War in Java Types of Events in Java MessageDigest in Java Longest Odd Even Subsequence in Java Java Variable Declaration Java Technologies List Java Localization Java Linters Java Macros Java Future Example Nth node from the end of the Linked list in Java Moran Numbers in Java Missing Number in an Arithmetic Progression in Java Minimum Window Subsequence in Java Minimum Number of Taps to Open to Water a Garden in Java Minimum Number of Platforms Required for a Railway Station Minimum Difference Between Groups of Size Two in Java Java SHA256 Java Snippets Java Speech Recognition Java Subtract Days from Current Date Java Project Ideas Majority Element in Java Longest Arithmetic Progression Sequence in Java Object Definition in Java Print Matrix Diagonally in Java Print Pencil Shape Pattern in Java Sparse Numbers in Java Split the Number String into Primes in Java Sylvester Sequence in Java Three Partition Problems in Java Banking Application in Java Brilliant Number in Java Convert Integer to Roman Numerals in Java Chromatic Number in Java Convert JSON to Map in Java Arrow Operator in Java Converting Long to Date in Java Count of Range Sum Problem in Java Finding Odd Occurrence of a Number in Java Generic queue in Java Hamming Code in Java Hashing Algorithm in Java Heap Implementation in Java Hybrid Inheritance in Java Internal Working of ArrayList in Java Java Binary Operators Java BLOB Java Coding Software Maximizing Profit in Stock Buy Sell in Java Median Of Stream Of Running Integers in Java Misc Operators in Java Nth Term of Geometric Progression in Java Self-Descriptive Numbers in Java Permutation Coefficient in Java Minimum Lights to Activate Java Snippet Class Java Console Java Developer Java Get File Size Java Image Java Interface Lock Java OCR Least Operator to Express Number in Java List of Constants in Java Loose Coupling in Java Order of Execution of Constructors in Java Inheritance Shift right zero Fill Operator in Java and Operator Shifting Shopping Bill in Java Sort Elements by Frequency in Java Spliterator in Java 8 Static Array in Java Ternary Operator in Java Tetris Game in Java Cast Operator in Java This Operator Using in Java Thread States in Java Tilde operator in Java Timestamp Operation in Java Untouchable Number in Java Various Operation on Queue using Linked List in Java Various operations on HashSet in Java Why are generics used in Java XOR Binary Operator in Java Anonymous Function in Java Flag Pattern in Java Ganesha’s Pattern in Java Heart Pattern in Java Getting Synchronized Set from Java HashSet India Map Pattern in Java InputMismatchException in Java Java Generate UUID Java Lock Java Thread Priority in Multithreading Lombok Java Morris Traversal for Inorder in Java Morris Traversal for Preorder in Java Ordinal Number in Java Polygonal Number in Java Sealed Class in Java Set Matrix Zeros in Java Swastika Pattern in Java Centered Square Numbers in Java Array Slicing in Java Block Swap Algorithm for Array Rotation in Java Bouncy Number in Java Byte to Hex in Java Camel Case in Java Bad Operand types for Binary Operator Java Comparetoignorecase in Java Creating API Document Javadoc tool Advantages of Generics in Java Computing Digit Sum of all Numbers from 1 to n in Java ConcurrentModificationException in Java Check Whether A Number Is A Power Convert IP to Binary in Java Creating a Custom Generic Class in Java Get year from date in Java Gregorian Calendar Java Current Date Grepcode Java util date Hierarchy of operators in Java Highest precedence in Java Java Map Generic Java Lambda foreach Java copy constructor Example Java Imageio Java Generics Questions Java extend multiple classes Getting the Day from the Date in Java Get yesterdays date by no of days in Java Dining Philosophers problem in Java Display List of TimeZone with GMT and UTC in Java Equilibrium Index of an Array in Java Find the Frequency of Each Element in the Array in Java Find Unique Elements in Array Java Stone Game in Java System Class in Java The Diamond Operator in Java 7 The Maximum Rectangular Area in a Histogram in Java Three-way operator in Java Types of Assignment Operators in Java Trimorphic numbers in Java Types of Bitwise Operators in Java Types of Garbage Collector in Java Types of Logical Operators in Java Union in Java URLConnection class in Java Use Of Adapter class in Java Various operations on the Queue using Stack in Java XNOR operator in Java Zygodromes in Java Memory Leak in Java Java Worker Class Java Sort String Local Minima in Java Mutable class in Java MOOD Factors to Assess a Java Program Model Class in Java Manachers Algorithm in Java Logger class in Java && operator in Java nth Prime Number in Java SHA Decrypt in Java Producer Consumer Problem in Java Using Synchronized Block Ramanujan Number or Taxicab Number in Java Undo and Redo Operations in Java Second Smallest Number in an Array in Java Set Value to Enum in Java

Find next greater number with same set of digits in Java

It contains a number (num). Finding the smallest number that has the same number of elements as num that is also larger than num is the task at hand. If num is the biggest number that can be formed using its digits, then it is impossible to find a bigger number, and a warning should be printed as a result.

Example

For input 89321 the expected output would be 91238

The following numbers are higher than the number 89123 and are composed of the numerals 1, 2, 3, 8, and 9.

98123, 98132, 98213, 98231, 98312, 98321, 93128, 93182, 93218, 93281, 93812, 93821, 92138, 92183, 92318, 92381, 92813, 92831, 91238, 91283, 91328, 91382, 91823, 91832

The least number among all of these is 91238.

Example

For input 3648 the expected output would be 3684

Numbers that are greater than 3648 and comprise the numbers 3, 8, 4, and 6 are:

3684, 4368, 4386, 4638, 4683, 4836, 4863, 6348, 6384, 6438, 6483, 6834, 6843, 8346, 8364, 8436, 8463, 8634, 8643

The least number among all of these is 3684.

Example

For input 9100 The next larger number cannot be determined.

The greatest number that can be constructed with the numbers 9, 1, 0, and 0 is 9100. Therefore, using the provided digits, it is impossible to find a value bigger than 9100.

Observation

Some of the crucial things to notice are listed below.

  • The conclusion is "It is just not possible to identify the next larger number" if a number's digits are arranged in descending order. 98675 is an illustration.
  • When a number's digits are arranged in ascending order, the last two numbers of the number must be switched. For instance, 4576 is the next higher number after 4567.
  • The other circumstances require starting the number processing from the rightmost edge since the smaller of the integers that are greater than the specified number must be found.

Algorithm

The procedure for calculating the next larger integer based on the observation mentioned above is as follows.

Step 1: Starting with the rightmost digit, traverse the integer num until you locate a digit that is smaller than the last digit you travelled. For instance, if the input number is "4975," one must halt at 4. Because 4 is smaller than the digit after it, 9, this occurs. Finding the next larger integer is impossible if such a digit is not obtained.

Step 2: Next, start looking again for smallest digit that is larger than the found digit "d" on its right side. The right-hand side of 4 has a value of 975 for the number 4975. The smallest number larger than four among the numbers 9, 7, and 5 is 5.

Step 3: Next, reverse the order of 4 and 5. One will so receive 5974. But among the largest, this amount is not the smallest. As a result, the numbers after digit 5 must be sorted. Thus, one can obtain 5479 by arranging all digits of the integer 5974. The number 5479, which consists of the digits 4, 9, 7, and 5, is the lowest among those bigger than 4975.

The formula for determining the next larger integer is given below.

  • Starting with the rightmost digit, explore the given number until you locate a digit that is lower than the one you have just visited. In the case of the input number "534976," for instance, we terminate at 4 because it is smaller than the subsequent digit (9). If we are unable to locate one such digit, the outcome will read "Not Possible."
  • Now look for the lowest digit greater than "d" on the right side of the found digit "d" above. The right-hand side of 4 includes "976" for "534976". The smallest number higher than four is six.
  • In the case above, if we swap the two digits we found above, we get 536974.
  • From the point adjacent to the letter "d" until the last digit, sort the numbers now. The output is the number we obtain after sorting. We sorted the numbers in bold 536974 for the example above. The result for input 534976 is "536479," which is the next higher number.

Using Permutation

It is a forceful strategy. Using the digits present in the supplied number num, we shall compute each number that can be created. These calculated numbers will be kept in a hash set, or hs. We shall choose a number from that hash set that is both less than and greater than the integer num.

Nextgrtnum.java

// importing all the requried packages 
import java.util.ArrayList;  
import java.util.HashSet;  
import java.util.Set;  
  
public class Nextgrtnum  
{  
public Set hash;  
// default constructor to the Nextgrtnum class  
Nextgrtnum()  
{  
hash = new HashSet();  
}  
// This method will help in finding the next greater number  
int nextgrt(int val)  
{  
int num = val;      
ArrayList arr = new ArrayList();  
// Using while loop to find the digits in the number with name val'
// and adding those digits to the array list in the reverse order 
while(num != 0)  
{  
arr.add(num % 10);  
num = num / 10;  
}  
  
// using permute method to permutate over all the 
// integers in the arraylist and passing the size of permutation.  
permute(arr, 0, arr.size() - 1);  
  
int answer = Min(hash, val);  
  
return answer;  
}  
  
// This method will find the next mini value 
// from the permute and returns the mini value with those set of digits
public int Min(Set s, int val)  
{  
int mini = Integer.MAX_VALUE;  
  
  
// from the set of integers s we are makking the array 
Integer[] arr = s.toArray(new Integer[s.size()]);  
  
  
// Finding the size of the array arr 
int len = arr.length;  
  
// taking a boolean variable f to indicate that the min is 
// found this will be true when the min is found.
boolean f = false;  
  
for(int i = 0 ; i < len; i++)  
{  
int t = arr[i];  
  
// the number should be greater than the original number 
// so this condition checks the greater number.  
if(t > val)  
{  
//  our goal is to find the min value
// of all the greater number from the same set of digits. 
if(mini > t)  
{  
mini = t;  
  
// as our min value is found we will 
// update our boolean value f to true.  
f = true;  
}  
}  
  
}  
  
  
// we will return the min value only if 
// the min val is found 
if(f)  
{  
return mini;  
}  
// If the control gets to this point,
// the mini value was not located. 
// therefore please return -1. 
return -1;  
}  
  
  
// Swap the value at positions x and y
// in the array list arr. 
public void change(ArrayList arr, int x, int y)  
{  
int i = arr.get(x);  
int j = arr.get(y);  
  
arr.set(x, j);  
arr.set(y, i);  
}  
  
// Create a number using the digits from the 
// array collection. Keep in mind that the order
// of the numbers in the val matches that of the array list.
// For instance, if arr = [2, 3, 6, 1, 1, 9, 8], 
// then 2361198 will be the result. 
int make(ArrayList arr)  
{  
int len = arr.size();  
int num = 0;  
  
for(int i = 0; i < len; i++)  
{  
num = num * 10;  
num = num + arr.get(i);  
}  
  
return num;  
  
}  
  
  
// a technique that uses the digits with in array list 
//arr to determine the possible numbers  
private void permute(ArrayList arr, int l, int r)  
{  
// this is a corner case   
if (l == r)  
{  
// Create the number that use the array list's digits,
// then add the result to the hash set.  
int val = make(arr);  
hash.add(val);  
}  
  
else  
{  
for (int j = l; j <= r; j++)  
{  
// Apply recursion, then alter once more to go backwards.  
change(arr, l, j);  
permute(arr, l + 1, r);  
change(arr, l, j);  
}  
}  
}  
  
  
// main method starts here   
public static void main(String[] argvs)  
{  
// object creation for the class Nextgrtnum  
Nextgrtnum nxtgrtnum = new Nextgrtnum();  
  
// Example 1  
int val = 536479;  
  
int answer = nxtgrtnum.nextgrt(val);  
  
System.out.println("The given in put is: " + val);  
  
if(answer != -1)  
{  
System.out.println("The following is the next higher number is: " + answer);  
}  
else  
{  
System.out.println("The next higher number is not feasible.");      
}  
  
System.out.println();  
  
nxtgrtnum.hash.clear();  
  
// Exampel 2  
val = 654321;  
  
answer = nxtgrtnum.nextgrt(val);  
  
System.out.println("The given in put is: " + val);  
  
if(answer != -1)  
{  
System.out.println("The following is the next higher number is: " + answer);  
}  
else  
{  
System.out.println("The next higher number is not feasible.");      
}  
  
  
System.out.println();  
  
nxtgrtnum.hash.clear();  
  
// input 3  
val = 4876;  
  
answer = nxtgrtnum.nextgrt(val);  
  
System.out.println("The given in put is: " + val);  
  
if(answer != -1)  
{  
System.out.println("The following is the next higher number is: " + answer);  
}  
else  
{  
System.out.println("The next higher number is not feasible.");      
}  
}  
}  

Output:

The given in put is: 536479
The following is the next higher number is: 536497


The given in put is: 654321
The next higher number is not feasible.


The given in put is: 4876
The following is the next higher number is: 6478

Complexity analysis: To discover the next larger number in the aforementioned programme, we used backtracking. As a result, the programme mentioned above has exponential time complexity. Let's say that num has d integers. The total amount of numbers in the hash set is therefore hs n!. As a result, the programme described above has an O(n!) space complexity.

Using the sorting method

Nextgrtnum1.java

// importing all the requried packages  
import java.util.ArrayList;  
import java.util.Collections;  
  
public class Nextgrtnum1  
{  
boolean changepss(ArrayList arrlis)  
{  
int len = arrlis.size();  
int j;  
  
// travesing the loop from right to left using the for loop  
for (j = len - 1; j > 0; j--)  
{  
int xel = arrlis.get(j);  
int yele = arrlis.get(j - 1);  
  
  
if (xel > yele)   
{  
// The processing begins here because we
// have a digit that is smaller than the next digit.  
break;  
}  
}  
  
  
if(j == 0)  
{  
// The numbers' digits are organised in descending order.
// As a result, the next higher number is impossible. 
return false;  
}  
  
int te = arrlis.get(j - 1);  
int least = j;  
  
// locating a digit that exceeds the digit at
// the (j - 1)th index. However, we must choose 
// the least number from the group of larger ones. 
for (int k = j + 1; k < len; k++)  
{  
if (arrlis.get(k) > te && arrlis.get(k) < arrlis.get(least))  
{  
least = k;  
}  
}  
  
// switching to obtain the higher number  
int xel = arrlis.get(j - 1);  
int yele = arrlis.get(least);  
arrlis.set(least, xel);  
arrlis.set(j - 1, yele);  
  
  
// Sorting the greater than num integers 
// to get the one that is the smallest 
Collections.sort(arrlis.subList(j, len));  
  
return true;  
  
}  
  
// a technique that locates the following larger number  
int Nextgrt(int num)  
{  
  
int val = num;      
ArrayList arrlis = new ArrayList();  
  
// loop for removing the digits from 
// the number num & adding them in the opposite
// order to the array list  
while(val != 0)  
{  
arrlis.add(val % 10);  
val = val / 10;  
}  
  
// changing the numbers' order while preserving the existing arrangement  
Collections.reverse(arrlis);  
  
// If the exchange is possible, 
// give the following larger number.  
if(changepss(arrlis))  
{  
int nextnum = 0;  
int len = arrlis.size();  
  
// creating a new number using a loop that
// combines the digits in the list to produce 
// the next larger number  
for (int j = 0; j < len; j++)  
{  
nextnum = nextnum * 10;  
nextnum = nextnum + arrlis.get(j);  
}  
  
// giving back the updated larger number 
return nextnum;  
}  
  
  
  
// if the control reaches here, then it means the next greater number is not   
// possible. Hence, -1 is returned  
return -1;  
}  
  
  
// main method starts here    
public static void main(String[] argvs)  
{  
// object creation for the class Nextgrtnum1  
Nextgrtnum1 Nextgrtnum1 = new Nextgrtnum1();  
  
// Example 1  
int num = 536479;  
  
int ans = Nextgrtnum1.Nextgrt(num);  
  
System.out.println("The given in put is: " + num);  
  
if(ans != -1)  
{  
System.out.println("The following is the next higher number is: " + ans);  
}  
else  
{  
System.out.println("The next higher number is not feasible.");      
}  
  
System.out.println();  
  
// Example 2  
num = 654321;  
  
ans = Nextgrtnum1.Nextgrt(num);  
  
System.out.println("The given in put is: " + num);  
  
if(ans != -1)  
{  
System.out.println("The following is the next higher number is:  " + ans);  
}  
else  
{  
System.out.println("The next higher number is not feasible.");      
}  
  
  
System.out.println();  
  
  
// Example 3  
num = 4876;  
  
ans = Nextgrtnum1.Nextgrt(num);  
  
System.out.println("The given in put is: " + num);  
  
if(ans != -1)  
{  
System.out.println("The following is the next higher number is: " + ans);  
}  
else  
{  
System.out.println("The next higher number is not feasible.");      
}  
}  
}  

Output:

The given in put is: 536479
The following is the next higher number is: 536497


The given in put is: 654321
The next higher number is not feasible.


The given in put is: 4876
The following is the next higher number is: 6478