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 How to run Java program in command prompt How to run Java program in Eclipse 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 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 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 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

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 Python vs Java 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 C vs 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 How to calculate time difference 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 String Tokenizer and Split Method in Java Difference Between BufferedReader and FileReader Difference Between Thread.start() and Thread.run()

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 create thread in Java How to find length of String 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 create custom exception in Java How to import packages in Java How to run applet Program in Java How to take Array Input in Java How to achieve abstraction 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

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 Servlet Tutorial

Java Servlets Tutorial

Java JSP Tutorial

Java JSP Tutorial

Hiberate Tutorial

Hibernate Tutorial

Spring Tutorial

Spring Tutorial

Spring MVC Tutorial

Spring MVC Tutorial

Jenkins Tutorial

Jenkins Tutorial Jenkins java net socket connection time out

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

Misc

List all files in a Directory in Java Nonagonal number in Java Null Pointer Exception in Java Package naming convention in Java Packages Program in java Pangram Program in Java PriorityBlockingQueue Class in Java Race Condition in Java Repdigit Numbers in Java Reserved Keywords 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 program to print matrix in Z form 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 Case Keyword Java Try-Catch Block Java Class KeywordJava concurrency interview questions Java Continue Keyword Java CountDownLatch Java Default Keyword Java Double Keyword Java Editors Java Else Keyword Java Enum Keyword Java Extends keywordJava Finally Keyword Java Font Example of Static import in Java How Many Ways to Create Objects in Java Implementing Queue Using Array in Java Instanceof operator in Java Interchange Diagonal elements in Java Java Arrays Fill Java Char Keyword Convert list to array Java Convert milliseconds to date in Java Copy data/content from one file to another in java CRC Program in Java Creating a Jar file in Java Crown Pattern in Java Difference Between Access Specifiers and Modifiers in Java Difference Between Java and PHP Difference Between replace() and replaceall() in Java Duodecimal in Java Finding middle node of a linked list in Java Group by in Java 8 Hollow Diamond Pattern in Java How annotations work in Java Java Boyer Moore Catalan number in Java Cosmic Superclass in Java Difference between this and super 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 Contextual keywords 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 What are Array strings 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 What is String 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 How to stop execution after a certain time in Java 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 What is string in Java why it's immutable 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 Star Program in 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 What is advance Java? 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 Java Break Keyword 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 Java Enumeration Compile-time Error in Java Java Get Time in UTC Java.sql.Time Format Structure of Java Program Thread Concept in Java Creation of Multi-Thread in Java Enterprise Java Beans POJO in Java Volatile keyword in Java Java Constant Collection Interfaces in Java with Examples Deadlock Prevention and avoidance in Java Java Boolean Keyword Java Byte Keyword Java List Implementations Java Xml Parser Method Overriding in Java RMI program in Java Virtual Function in Java What is interpreter 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 What is anagram in Java? Accessors and Mutator in Java Bottom view of a binary tree in Java Convert List to String in Java Equidigital in Java How to check data type 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 How to Reduce Time Complexity 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 The final Keyword 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 Caesar Cipher Program 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 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 Tug of War in Java Types of Events in Java

Streams in Java

The conventional Java SE 8 version came with many new peculiarities, out of which the most striking of which are assuredly lambda expressions and the method references. Streams and Streams API are also some of the most outstanding characteristics in Java SE 8. Many projects are enhanced to Java 8 to use the friendly lambda expressions syntax and the Java streams.

Java implements a newly added package in Java SE 8 known as java.util.stream. The package contains many different interfaces, classes, and enum that allows the user to perform functional-style operations on the elements. The entire idea of the Java streams is to facilitate functional-style processes on streams of elements.

A Java stream cannot be said to be a data structure. However, we can say that Java Stream is an abstraction. However, Java Streams is not a collection or set where we can save elements and store data. The primary relevant difference between a structure and a stream is that a stream doesn’t store the data and components. A stream is a reflection of a non-changeable compilation of processes that are applied in any classification of the data.

In simple words, a Java Stream is a package that contains various classes and interfaces that are capable of doing the iteration of its own elements internally. Conversely, when we are working with iteration characteristics of the Java Collections, then we have to perform the iteration of the elements personally. For example, we can use a Java Iterator or the Java for each loop in order to work with a Java Iterable.

Characteristics of Java Stream

Java Stream describes a series of objects from an origin that supports aggregate processes. There are many characteristics of Java Streams. These characteristics are given as follows:

  • No storing of elements: The Java streams simply carry elements from a source such as an I/O channel, an array, a data structure, or a Collections framework through a pipeline of computational operations.
  • A sequence of elements: A Java stream implements a collection of elements of a particular kind in a subsequent manner. A stream only prepares and computes elements on demand. It never saves the data components.
  • Functional in nature: The Java streams are also functional in nature. By functional nature, we can say that all the processes executed on a Java stream do not change their origin. For example, when we filter a Stream that is collected from a source, it creates a new distinct Stream that does not contain the elements that were filtered. However, it will remove those elements from the source collection.
  • Aggregate operations: Java Stream also provides support for aggregate processes and intermediate operations like map, limit, reduce, match, filter, find, and many more.
  • Automatic Iterations: All the iterations and traversal are done internally in Java Stream processes and methods over the different source elements. Whereas in the Collections framework, there is a need for explicit iteration.
  • Lazy nature: Java Streams are very lazy. A code is only evaluated in the Java stream when it is required. This lazy nature is beneficial as it saves a lot of time.
  • Pipelining: The operations (or Stream operations) that return stream to itself so that we can pipeline their result are known as intermediate operations. The principal function of intermediate operations is to take the input, process the accepted input, and return particular output to the destination. The method which is usually present at the end of the pipelining process that marks the end of the Java stream, is the collect() method.
  • Source of Java Streams: The Java stream takes Collections, Arrays, or I/O sources as the input references.

Creating Java Streams

In Java SE 8, there are many different methods or ways to create a Java stream. These methods are given below -

Stream.of() - The Java stream.of() method is used to generate a stream of the fixed quantity of elements.

Example of Stream.of()

StreamOfExample.java

import java.util.stream.*;

public class StreamOfExample

{

     public static void main(String[] args)

     {

         Stream<String> strm = Stream.of("ab","cd","ef","gh","ij","kl","mn");

         strm.forEach(str -> System.out.println(str));

     }

}

Output:

ab

cd

ef

gh

ij

kl

mn

Stream.of(array): The Java stream.of(array) method is practiced to produce a stream from the array. The elements of the stream created are taken from the array elements.

Example of Stream.of(array)

StreamOfArrayExample.java

import java.util.stream.*;

public class StreamOfArrayExample

{

     public static void main(String[] args)

     {

         Integer arr[]=new Integer[5];

         for(int i=0;i<5;i++){

             arr[i]=i+1;

         }

         Stream<Integer> stream = Stream.of(arr);

         stream.forEach(n -> System.out.println(n));

     }

}

Output:

1

2

3

4

5

List.stream(): The Java List.stream() method is used to generate a stream from the list. The elements of the stream created are taken from the list elements.

Example of List.stream()

ListStreamExample.java

import java.util.stream.*;

public class ListStreamExample

{

     public static void main(String[] args)

     {

         ArrayList<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

         Stream<String> stream = names.stream();

         stream.forEach(str -> System.out.println(str));

     }

}

Output:

Mohit

Prateek

Arun

Nishkarsh

Daksh

Nirbhay

Ayush

Anshul

Stream.generate(): The Java Stream.generate() method is used to create a stream from the generated elements. In the example given below, we have used the Random() method to generate a stream of random integers.

Example of Stream.generate()

StreamGenerateExample.java

import java.util.stream.*;

public class StreamGenerateExample

{

     public static void main(String[] args)

     {

         Stream<Integer> stream = Stream

         .generate(() -> (new Random()).nextInt(50));

         stream.limit(10)

         .forEach(System.out::println);

     }

}

(Output may vary in every execution as we are using the Random() method, that generates random integers at every execution).

Output:

18

11

31

38

5

28

19

19

18

36

In the above example, we are creating a stream of 10 random integers by restricting the element count of the stream to 10 with the help of the limit() method.

Common operations of Java Streams

Java Stream holds two different types of operations. These operations are:

  • Intermediate operations: Intermediate operations are the operations that return a stream so that the user can chain various intermediate operations without using semicolons, as we do in other programming languages like Scala.
  • Terminal operations: The terminal operations are the operations that are mainly void and null, and if not null, these operations return a non-stream as a result.

Different Intermediate Operations:

As we have stated earlier that the intermediate operations return the stream itself so we can chain multiple method calls in a row.

Different intermediate operations in Java are:

  • Stream.filter(): The Java Stream filter() method is one of the major operations under intermediate operations. The filter() method accepts a Predicate to separate all components of the stream. This operation is under intermediate operations because it enables the users to call another stream operation.  For example, Stream.forEach() method) on the result. The predicate should declare true if the component is to be introduced in the final Stream, and the Predicate will reflect false if the component should not be included in the final stream.

Example of Stream.filter()

StreamFilterExample.java:

            import java.util.*;

public class StreamFilterExample

{

                        public static void main(String[] args)

                        {

                                ArrayList<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

        names.stream().filter((s) -> s.startsWith("A")).forEach(System.out::println);

                        }

}

Output:

Arun

Ayush

Anshul
  • Stream.map(): The intermediate operation Stream.map(), with the help of the given function, transforms each component in the stream into some other object. In simple words, the Stream.map() operation converts the element of a stream into something else. It takes the given function and applies that function to every element of the stream, which at the end returns a stream of the values that are produced by the parameter function. It also supports the user to create a calculation on the data inside a Java stream.

For example, if a user has a list of strings, the user can transform each string from the given list to uppercase, lowercase, or to a substring of the original string and something entirely else.

Example of Stream.map()

StreamMapExample.java

            import java.util.*;

public class StreamMapExample

{

     public static void main(String[] args)

     {

        ArrayList<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

       names.stream().map(String::toUpperCase)

        .forEach(System.out::println);

     }

}

Output:

MOHIT

PRATEEK

ARUN

NISHKARSH

DAKSH

NIRBHAY

AYUSH

ANSHUL
  • Stream.sorted(): The Java Stream sorted() method is also an intermediate operation or method. This sorted() operation returns a classified (or we can say the sorted) view of the stream. The components in the stream are sorted in a normal manner unless the user passes or uses a custom Comparator if they want to sort the stream in a different manner.

Example of Stream.sorted()

StreamSortedExample.java

            import java.util.*;

public class StreamSortedExample

{

     public static void main(String[] args)

     {

        List<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

       names.stream().sorted()

        .forEach(System.out::println);

     }

}

Output:

Anshul

Arun

Ayush

Daksh

Mohit

Nirbhay

Nishkarsh

Prateek

Different Terminal Operations

As we stated earlier that Terminal operations are the operations that return a result of a particular type after doing processing on all the elements of the stream. As soon as the terminal operation is invoked of the given stream, the iteration of the given Stream and any of the chained streams will get started. After completing the iteration on the stream, the result of the applied terminal operation is returned.

Different Intermediate operations in Java are as follows:

  • Stream.forEach(): The Java Stream forEach() method or operation is one of the terminal operations in which starts the internal iteration of the components in the stream.  

In simple words, the Java Stream forEach() method helps in repeating over all of the components of a stream and execute some process on each of them. The forEach() method returns nothing, or we can say void. The process to be performed on the elements of the stream is transferred as the Java lambda expression.

Example of Stream.forEach()

StreamForEachExample.java

import java.util.*;

public class StreamForEachExample

{

     public static void main(String[] args)

     {

        ArrayList<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

       names.forEach(System.out::println);

     }

}

Output:

Mohit

Prateek

Arun

Nishkarsh

Daksh

Nirbhay

Ayush

Anshul
  • Stream.collect(): The Java Stream.collect() method is practiced to take elements from a stream and save all of them in a group. It is a method to get away from the environment of streams and receive a solid combination of values, like an array list or a list. The Java Stream collect() method is a terminal operation that starts the internal iteration of elements and collects the elements in the stream in a collection or object of some kind.

Example of Stream.collect()

StreamCollectExample.java

            import java.util.*;

            Import java.util.stream.Collectors;

public class StreamCollectExample

{

     public static void main(String[] args)

     {

        List<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

       List<String> namesInUppercase = names.stream()

                            .map(String::toUpperCase)

                            .collect(Collectors.toList());

     System.out.print(namesInUppercase);

     }

}

Output:

[MOHIT, PRATEEK, ARUN, NISHKARSH, DAKSH, NIRBHAY, AYUSH, ANSHUL]
  • Stream.match() :  The Java Stream includes various matching operations that can be used to indicate whether a provided predicate resembles the elements of the stream or not. There are many different matching operations in Java Stream. The result returned by all the matching operations is of type boolean.

Different matching operations under Stream terminal operations are:

  • Stream anyMatch():  The anyMatch() method of Java stream is also one of the terminal operations that inputs a single Predicate or condition as a parameter and starts the internal iteration of the Stream. It implements the Predicate parameter to every component of the Stream. If the given Predicate reflects true for any of the components of the stream, the method yields true. If no elements match the Predicate, the method returns false.

Example of Stream anyMatch() method

StreamAnyMatchExample.java

import java.util.*;


public class StreamAnyMatchExample
{
     public static void main(String[] args)
     {
        List<String> names = new ArrayList<>();


        names.add("Mohit");
        names.add("Prateek");
        names.add("Arun");
        names.add("Nishkarsh");
        names.add("Daksh");
        names.add("Nirbhay");
        names.add("Ayush");
        names.add("Anshul");
       boolean result = names.stream()
        .anyMatch((str) -> str.endsWith("h"));
 
       System.out.println(result);
     }
}

Output:

true
  • Stream allMatch(): The allMatch() method of Java stream is also one of the terminal operations that inputs a single Predicate or condition as a parameter and starts the internal iteration of the Stream. It implements the Predicate parameter to every component of the Stream. If the given Predicate reflects true for all of the components of the stream, the method yields true.  If not all the elements match the Predicate,the method returns false.

Example of Stream allMatch() method

StreamAllMatchExample.java

import java.util.*;


public class StreamAllMatchExample
{
     public static void main(String[] args)
     {
        List<String> names = new ArrayList<>();


        names.add("Mohit");
        names.add("Prateek");
        names.add("Arun");
        names.add("Nishkarsh");
        names.add("Daksh");
        names.add("Nirbhay");
        names.add("Ayush");
        names.add("Anshul");
       boolean result = names.stream()
        .allMatch((str) -> str.endsWith("h"));
 
       System.out.println(result);


     }
}

Output:

false
  • Stream noneMatch(): The noneMatch() method of Java stream is also one of the terminal operations that inputs a single Predicate or condition as a parameter and starts the internal iteration of the Stream. It implements the Predicate parameter to every component of the Stream. It returns true if no elements are matched by the Predicate and returns false if one or more elements are matched with the predicate.

Example of Stream noneMatch() method

StreamNoneMatchExample.java

import java.util.*;


public class StreamNoneMatchExample
{
     public static void main(String[] args)
     {
        List<String> names = new ArrayList<>();


        names.add("Mohit");
        names.add("Prateek");
        names.add("Arun");
        names.add("Nishkarsh");
        names.add("Daksh");
        names.add("Nirbhay");
        names.add("Ayush");
        names.add("Anshul");


       boolean result = names.stream()
        .noneMatch((str) -> str.endsWith("h"));
 
       System.out.println(result);


     }
}

Output:

false
  • Stream.count(): The Java Stream count() method is also a terminal operation that reflects the number of components present in the stream. The number of elements present in the stream is produced and returned in the form of a long return type. In simple words, the Java Stream count() method starts the internal iteration of the elements in the Stream and counts the elements present in it.

StreamCountExample.java

import java.util.*;

public class StreamCountExample

{

     public static void main(String[] args)

     {

        List<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

       long count = names.stream().count();

       System.out.println(count);

     }

}

Output:

8
  • Stream.reduce(): The Java Stream reduce() method is also a terminal operation that helps in reducing all the components of the stream to only a single component. It performs a reduction on the components of the stream with the provided function. The result of the reduce() method is an Optional (Optional is a process of restoring a nullable T reference with a non-null value), which holds the reduced value of the stream.

StreamReduceExample.java

import java.util.*;

public class StreamReduceExample

{

     public static void main(String[] args)

     {

        List<String> names = new ArrayList<>();

        names.add("Mohit");

        names.add("Prateek");

        names.add("Arun");

        names.add("Nishkarsh");

        names.add("Daksh");

        names.add("Nirbhay");

        names.add("Ayush");

        names.add("Anshul");

       Optional<String> reducedString = names.stream()

        .reduce((str1,str2) -> str1 + "*_*" + str2);

       reducedString.ifPresent(System.out::println);

     }

}

Output:

Mohit *_* Prateek *_* Arun *_* Nishkarsh *_* Daksh *_* Nirbhay *_* Ayush *_* Anshul

Important Points to remember about Java Streams

  • A Java stream is not a data structure. However, it receives input from the Collections, Arrays, or I/O channels.
  • Java Streams never alter the primary data structure. In Java Streams, the result is given as per the pipelined methods.
  • Java Stream contains two types of operations. These are terminal operations and Intermediate operations.
  • Every intermediate operation is lazily performed, and it returns a stream as a result, hence multiple intermediate operations can be pipelined. At the same time, all the terminal operations indicate the termination of the stream and return the result.

Conclusion

The Java Streams are very efficient and simple to understand methods. Java Streams contains a collection of tools that are helpful in processing the series of elements. When Streams are used correctly, it allows us to reduce a considerable amount of boilerplate code, create more readable programs, and advance an app’s productivity.



ADVERTISEMENT
ADVERTISEMENT