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 Multiple Inheritance Programs in Java Prime Number Program in Java Using a Scanner Program to Reverse a Number in Java Fibonacci series program in java using multithreading

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 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


Java Serialization Java transient


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


Java AWT


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 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 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 Array Vs ArrayList in Java Difference between Fork Join Framework and Executor Service in Java Difference between Jdeps Jdeprscan in Java Difference between Wait and Notify 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 How to Solve the Deprecated Error in Java How to Return Value from Lambda Expression Java How to Read CSV Files in Java How to Change the Day in the Date using Java How to Calculate Week Number From Current Date in Java How to Calculate Time Difference Between Two Dates in Java How to Calculate the Time Difference between Two Dates in Java How Many Ways to Create an Object in Java How to Develop Programming Logic in Java How can we achieve abstraction in Java How to create abstract class in Java How to use api 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() Math.multiplyExact()

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 Static 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 Strictfp Keyword Java Switch Keyword Java Transient Keyword Java Volatile Keyword Java While Keyword Java Throw and Throws Keyword Synchronized Keyword in Java Java Super Keyword

Java Problems

3N+1 problem program in Java Ad Hoc Problem on Arrays in Java Alice and Bob Problem Java Alien language problem in Java Bin Packing Problem Java flour pack problem in Java Hourglass problem in Java Activity selection problem in Java Bounded buffer problem in Java Diamond problem in Java Dutch National Flag Problem in Java Monsoon Umbrella Problem in Java Producer consumer problem in Java using Synchronised block Coin change problem in dynamic programming Salesman Problem in Java Sleeping Barber Problem in Java Skyline Problem in Java Sliding Window Problem in Java Snake and Ladder Problem in Java Stable Marriage Problem in Java Davis Staircase Problem in Java Graph Problems in Java Sales Tax Problem in Java Stock Span Problem Using Stack 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 Can we override Private Method in Java Can Abstract Classes have Static Methods in Java What is the ambiguity problem in Java Can we create object of abstract class in Java Why do we use abstract class in Java

Java Interview Questions

Enum Java Interview Questions Java concurrency interview questions String Coding Interview Questions in Java


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 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 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 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 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 Java Code Coverage Tools Console Errors in Java Java md5 Hash Example If Condition in Lambda Expression Java Java Code Optimization Java Enum Java Error Stack Trace Java Flags Enum Java Heap Space Out of Memory Error Java Thread Dump Analyzer Kong Java Client Nested Enum in Java Switch Case with Enum in Java Time Class Operation in Java Delete a Cycle from a Linked List in Java Java Append Data to File Java RandomAccessfile Java Rename File Java Swings Java Try Resource Java Write File Java Maven Silicon Modules in Golang Creating a file using multithreading in Java Different ways to do multithreading in Java File handling using multithreading in Java Four player card game Java Multithreading Getting first date of month in Java Implicit Typecasting in Java Importance of thread synchronization in Multithreading in Java Java lambda filter example Java Memory Model Multithreading Java Sleep Java tricky code snippets Multithreaded lru cache in Java Neon Number in Java Prime number using multithreading in Java Read large xml file in Java multithreaded Role of join function in multithreading in Java String reverse preserving white spaces in Java Use of abstract method in Java Java Abstract factory pattern Java Single Linkedlist Abstract Declaration in Java Abstract Factory in Java Abstract for java mini project Abstract for Java project Advantages of abstraction in Java AWS Lambda Java Maven Adding Manychat Java Snippet to Thrive Theme Abstract implement interface in Java Addition Program Call by Reference Using Multithreading in Java Advanced Java Code Snippets Advantages of Multithreading Over Multitasking in Java Apache Camel Multithreading in Java Array of Class Objects in Java Autobiographical Number in Java AWS lambda Java example api gateway AWS Lambda Java Gradle AWS Lambda Java SDK AWS Lambda Java Spring Boot AWS Lambda Java Tutorial AWS Lambda REST API Java Benefits of Multithreading in Java Boundary Value Problem ODE in Java 2d Array Sorting in Java A Group Chat Application in Java Access Modifiers For Classes or Interfaces in Java Card Flipping Game in Java Duplicate Class Error in Java Giuga Numbers in Java Java Integer Reverse Method Methods Of GSon in Java Selection Statement in Java Dead Code in Java Find the index of an Array Element in Java K Closest Points to a Given Target Point in Java Last Non Zero Digit of a Factorial in Java Meta Class in Java Unreachable Code Error in Java

How to Create an API in Java?


The API can be abbreviated as Application Programming Interface. An API is a combination of set of classes and interfaces. It is also equivalent to a simple java program. To know about API let us go in to the flashback of Java Development Kit (JDK)

The JDK consists of three important components. They are:

  1. Java Virtual Machine
  2. Java Compiler
  3. Java Application Programming Interface

Java Virtual Machine

The Java Virtual Machine can be simply called as JVM. JVM converts the machine understandable byte code into user understandable output.

Java Compiler

The Java Compiler converts the given Java code into byte code format.

Java Application Programming Interface

The API Library contains classes and interfaces along with JDK. After referring API classes and interfaces, the programmer can easily use the API code for creating their own Java Program. The API’s are used to establish a bridge between two or more different applications.

Users of Java API

The Java Developers use the Java APIs based on their types of projects. There are three types of Java Developers who use Java APIs. They are

  1. Open Developers
  2. Internal Developers
  3. Partner Developers

Open Developers

Some well-known businesses provide developers open-source access to their APIs. These companies give customers access to APIs using a key so the business may control how the API is used.

The Applications which use these kinds of internal APIs are basically used in B2C.


By specifying the HTTP endpoint URL and the authentication for the API request, an API connector provides Azure AD B2C with the information required to contact API endpoints.

The Projects developed by Open Developers are like Twitter.

Internal Developers

Internal Developers use these kinds of APIs only while working for an organization. These kinds of APIs are accessible to the internal developers only. These APIs are only allotted to the internal developers of a single organization.

The Applications which these kinds of internal APIs used are B2B, A2A, B2C, B2E, etc.

These Internal Developers develop projects like Instagram, Facebook, Gmail, etc.

Partner Developers

The Partner Developers use Partner APIs which are created and used by organizations that build communications. Partner developers get access to these APIs using API keys.

The Applications which these kinds of internal APIs used are B2B, B2C, etc.

Contents of Java API

The Java Developed API includes

  1. Applet Packages
  2. Abstract Window Tool Kit
  3. Graphics
  4. Graphical User Interface
  5. Swing Packages
  6. Input / Output Packages

Frames in API

  • All API components are displayed in the first frame (classes and packages).
  • When a specific package is chosen, all of its interfaces, classes, and exceptions are displayed in the second frame.
  • An overview of all API packages is given in the third and main frames, which may be enlarged to display the index, class hierarchy, and help sections.

Features of an API

Multiple Screens

Streamline the processes that users may view a variety of alternatives on a single screen thanks to social networking programs like Twitter, Facebook, LinkedIn, and Instagram. This feature is made available using Java APIs.

Business Field

Many businesses reveal private data as a result of the public release of APIs in order to inspire fresh ideas, address issues in current software, and discover new methods to enhance operations. An API that provides programmers with private API keys so they may access Twitter data and create apps is the Twitter developer account.

Banking and other important Applications

Online banking has permanently altered the sector. The APIs enable clients to easily manage their funds online.

Advantages of an API


Content may be generated once and automatically published or made accessible to several channels by granting API access. Content from your organization is prepared for simple sharing and redistribution to further your goal by reaching more citizens.


APIs enable computers to manage workloads that would otherwise need humans to do manual tasks. One straightforward way to accomplish this is to have a single content change spread simultaneously over a number of different website parts. However, APIs allow your team and your agency to alter workflows more generally, allowing for fewer steps and more efficiency.

Wider Reach

APIs may be used to disseminate services and information to new audiences and in certain settings that can be adjusted to offer individualized user experiences by enabling anybody to develop a new presentation layer, such an app, a website, or a widget. Apps or other websites that users frequently visit can be used to provide information or services about your organization to those who do not visit your website.


The American people have paid for the data and information that the federal government produces. Data that was previously solely accessible to a select few may now be more widely available thanks to APIs.

Mixing of Applications

By combining your knowledge with that from other sources, the public can better comprehend it. A minor, crucial component of another service might be an agency service or data stream. Consider all the applications for location data, including route planning, service check-ins, and finding the closest gas station. Although it is not the primary function of the program, location data makes it work.


In order for information or a service to be used in mobile apps, API access must be provided. The first stage is granting API access to the elements that would go into a mobile app, offering flexibility in the delivery of information and services, regardless of whether the objective is to enable agency-created applications or third-party apps. As the API provides a shortcut to the second, third, and fourth applications, this is especially important if agencies want to create more than one app.


Like-minded companies and non-profit organizations that are interested in leveraging agency information and services to deliver services support each agency's goal. They accomplish this by ingesting agency content, repurposing it into fresh, valuable products, and displaying agency content to their clients and customers. Any citizen with a brilliant concept may develop the upcoming "killer app" for your community, which can encourage innovation.


The ability to adapt sessions with the information and services that are most helpful to the individual user, businesses, and non-profits.


APIs aid in supporting future usage that was not expected when needs evolve. Making data accessible via API can support data migration that is quicker and simpler, as well as better data quality review and cleanup. With the use of APIs, services may be delivered with more flexibility, for instance by employing a service to access a backend system to power a new product.

Types of Java APIs

There are four types of Java APIs developed

They are

  1. Public
  2. Private
  3. Partner
  4. Composite


Java APIs that are public or open are provided with the JDK. There aren't any rigid limitations on how developers may utilize them.


Only those who work for a particular organization can access private (or internal) APIs, which are created by that organization.


Partner APIs are created by companies for strategic business operations and are regarded as third-party APIs.


Developers create composite APIs, which are micro services, by fusing various service APIs.

The most commonly used APIs are

  • Java Help
  • Twitter.4j
  • Java Persistence API
  • Association of the Standardization of Embedded Platforms
  • Android API
  • Web API
  • RESTful API

Data and API Service

This kind of technique is used to categorize Java APIs other than Private, Composite, Public, and Partner. These APIs are divided on the basis of their various properties offered. This includes:

  • CRUD
  • Internal API Services
  • User Interface Services
  • External API Services


Using standardized storage-unit connection tools like Java Database Connectivity, CRUD APIs allow data manipulation operations over diverse data storage units, including software as a service (SaaS) and relational database management systems (RDBMS) (JDBC).

Internal API Services

Internal API services are created to provide businesses with services tailored to their needs. Only internal processes and complicated data activities are included in these services.

External API Services

Developers can incorporate open-source external APIs into an already-existing application or website.

User interfaces Services

Open-source user interface service APIs let programmers create user interfaces for computers, smart phones, and other electronics.

Next, let's look at the guidelines and conventions that Java APIs adhere to. The rules and protocols to be followed are very strict.

The examples of Java Developed APIs are:

Applet Packages

They are depreciated from Java. So, the Applet API is not going to compile or run in a java compiler.

 Abstract Window Tool Kit ( AWT )

The AWT API Package is usually used to create a Pop up Window, Text Box, Buttons, Labels, Text Areas, etc.

Example Program:

File Name : Calci . java


  1. The class name  with main method must be the file name
  2. The class always starts with capital letter
// this is a program for simple calculator program
// you guys are going to have fun with it while executing this piece of code

import java.awt.*;

import java.awt.event.*;

import java.util.*;;

import java.lang.*;

public class Calci extends Frame implements ActionListener


TextField t1, t2,t3;   

Button b1,b2,b3,b4;


t1 = new TextField();

t2 = new TextField();
t3 = new TextField();

b1 = new Button("+");

b2 = new Button("-");

b3 = new Button("*");

b4 = new Button("/");


setLayout(new FlowLayout());














addWindowListener(new WindowAdapter()

public void windowClosing(WindowEvent we)





public void actionPerformed(ActionEvent e)
String tx1= t1.getText();

String tx2= t2.getText();

int a =Integer.parseInt(tx1);

int b =Integer.parseInt(tx2);

int c;

String a1;



c= a+b;






c= a-b;






c= a*b;





c= a/b;





public static void main(String args[])


new Calci();



For these kinds of user interactive programs, please execute them and see the working of it. The user is definitely going to enjoy these interactive programs.

Output Window:

How to Create an API in Java

This is how the output window is going to look. Have fun with it guys.


The Swing API is a collection of expandable GUI Components that makes it easier for developers to create Front End/GUI Applications using Java. Since it features nearly all of the controls that are equivalent to AWT controls, it is built on top of AWT API and serves as a replacement for AWT API.

Example Program

File Name : Swin . java

// This is a swing program written to divide two numbers
// Execute to enjoy it
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Swin extends JFrame implements ActionListener
JLabel L1,L2,L3;
JTextField T1,T2,T3;
JButton B1;
Swin ()
setTitle("Number Operations");
Container contentPane=getContentPane();
FlowLayout f=new FlowLayout();
L1 =new JLabel("Enter Num1 :");
T1 = new JTextField(15); //TextField for Numl
L2=new JLabel("Enter Num2 ");
T2= new JTextField(15); //TextField for Num2
L3=new JLabel("The Result :");
T3 =new JTextField(15); //TextField for result

B1=new JButton("Divide");
contentPane.add(B1); //Button to invoke division operation
public void actionPerformed(ActionEvent e)

int a=Integer.parseInt(T1.getText());
int b =Integer.parseInt(T2.getText());
Float c =Float.valueOf(a/b);
catch(NumberFormatException e1)
JOptionPane.showMessageDialog(this,"Not a valid number");
catch(ArithmeticException e2)
public static void main(String args[])
new Swin();

Output window:

How to Create an API in Java

Differences between AWT and Swing

                                AWT                                     Swing
AWT package name is awtSwing package name is swing
It is imported as “ import java . awt . *It is imported as : import javax . swing . * ;
AWT is not a part of Java Foundation ClassesSwing is a part of Java Foundation Classes  
The operating system has a major impact on the AWT components.The operating system is not a requirement for the Swing components. It is entirely written in Java language.
Most AWT Components' appearance cannot be modified. Generally speaking, it is based on how the operating system looks and feels.The Swing Components enable pluggable look and feel and are highly configurable.
AWT for Java has 21 peers. There is one peer for the discourse and one peer for each control. The operating system itself acts as a peer by providing peers in the form of widgets.Only the OS's window object serves as Java Swing's peer, providing the drawing surface for the widgets (labels, buttons, entry fields, etc.) created directly by the Java Swing Package.
Java AWT is slower than swing in terms of performance.      Java Swing is faster than the AWT.


The Graphics class is the abstract foundation class for all graphics contexts that enable an application to draw onto off-screen pictures as well as onto components that are realized on various devices.

It is similar to paint in our computer. But for Graphics class we need to write a simple java program. We used Graphics class widely in Applets. But in newer versions Applets were depreciated. Let us learn about Graphics class using AWT package.

Example Program

File Name: D1 . java


  1. The class name  with main method must be the file name
  2. The class always starts with capital letter
// Explaining about graphics package

import java .  io.*;
import java.awt.*;
import java . awt . event.*;
class D1 extends Frame
D1 ( )
// Setting Background
//close the frame
this.addWindowListener(new WindowAdapter()
public void windowClosing(WindowEvent we)
public void paint(Graphics g) //to display message in frame window
g.drawOval(90,70,80,80); //face
g.drawOval(110,95,5,5); //eyes
g.drawOval(145,95,5,5); //eyes
g.drawLine(130,95,130,115); //nose

public static void main(String s[])

D1 f=new D1();

Output Window

How to Create an API in Java

Graphical User Interface

The Graphical User Interface is shortly termed as GUI. The elements of a GUI are kept in containers known as forms in Java applications. GUI forms can be created using a collection of user interface components that are provided by the Java programming language. The GUI is widely used to create forms.

The IDE offers a number of features to make creating GUIs simpler, including:

Navigator Window

Navigator window shows a tree hierarchy of every element present in the form that is presently open. The things that are displayed include both visual and non-visual elements, such as timers and data sources, as well as visual elements and containers, such as buttons, labels, menus, and panels.

GUI Builder

GUI Creator is the primary area in the IDE where GUI design is done. By positioning components where you want them and offering visual feedback in the form of guidelines, the GUI Builder lets you layout forms.

Palette Window

Palette Window is   a list of every element that can be included in forms. The window can be configured to merely show icons or to display icons along with component names.

Properties Window

Properties window reveals the editable parameters for the component that is presently chosen.

Connection Wizard

Connection wizard helps set events between form components without the need to manually write code.


Manager allows you to add, remove, and arrange window components like Layouts, beans, Swing components, and AWT components.

The Beans Binding specification, which offers a means to synchronize the values of various bean properties, is also supported by the IDE. The development of desktop database applications is also made easier by this support.

Creation of GUI Application steps

  • Create Forms
  • Edit Forms
  • Preview Forms
  • Deploy the GUI Application

GUI Form Types

Form TypeExplanation
JAppletProgram used by an applet viewer or web browser with Java support.
JDialogModel or modeless input window for users.
JFrameAn application window which holds different properties
JPanelA portable container for holding interface components. The container can then be used in any other container, including a component of a JFrame , JPanel, JApplet, or JDialog.
AWTVisual forms that are based on the AWT. The AWT forms include Applet, Dialog, Frame, and Panel

Input / Output Package

Provides for system input and output through data streams, serialization and the file system.


A stream is a sequence of data. In Java, a stream is composed of bytes. It's called a stream because it is like a stream of water that continues to flow.

Input Stream

When reading data from a source which could be a file, an array, a peripheral device, or a socket, a Java application utilizes an input stream.

Output Stream

The class Output Stream is abstract. All classes that represent an output stream of bytes inherit from this super class. Bytes from an output stream are received and sent to a sink.

This package is used for basic input and output statements of a java program.

This is all about APIs in Java.