Java Tutorial

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

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 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 BufferedWriter Java InputStreamReader Java File Java Read File Line By Line Java FileOutputStream Jar File in Java

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 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

Java Differences

Java vs JavaScript Python vs Java Kotlin vs Java Java vs C++ C# vs Java Static vs Non-static in Java C vs Java int vs Integer in Java Stack vs Heap in Java Java Array vs ArrayList

How to

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 call a method in Java How to sort an array 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 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 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 achieve abstraction in Java How to call static 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 Parallel Arrays Sort in Java

Java 9 Features

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

Java Servlet Tutorial

Java Servlets Tutorial

Java JSP Tutorial

Java JSP Tutorial

Hibernate Tutorial

Hibernate Tutorial

Spring Tutorial

Spring Tutorial

Spring MVC Tutorial

Spring MVC Tutorial

Jenkins Tutorial

Jenkins Tutorial

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.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

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 Char and String differences in Java Difference between String, StringBuffer and StringBuilder 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 calculate time difference in Java 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

Process and Thread in Java

Process

It is a program that is running on your computer. The process is a heavy-weight, which takes memory separately to other processes. The process may be a small background task like spell-checker; it may be internet explorer or Microsoft word. All processes have one or more threads. The process performs a series of operations on a set of data.

The processes are created, scheduled, and terminated by the operating system for the use of the CPU. The operations of the process are controlled with the help of PCB (Process Control Block). PCB can be considered as the brain of the process having all the crucial information of a process like its process id, priority, state, contents CPU register, and PWS.

PCB is considered as the kernel-based data structure, which provides the three kinds of functions which are scheduling, dispatching, and context save.

Scheduling: It chooses(decides) which process is (run)executed first in the CPU.

Dispatching: An environment is set up for the execution of the process.

Context save: It saves the information regarding a process when it gets resumed or blocked.

Process and Thread in Java

The process is a program in execution. The operating system has to allocate the resources; every process uses these resources and releases the resources on the process termination. These increase the responsibility of the operating system to provide all these resources to a process. In turn, the operating system has a burden to manage these processes and to schedule the process. If there are many processes created in the system, a point will come where the operating system will not be able to allocate these resources to any process, and in turn, the system will get hung.  To solve this concept of threads was implemented.

The process life cycle has certain states included, such as ready, running, blocked, and terminated. For consisting of the track of the processing activity at an instant, its states are used.

Processes provide the medium to achieve the concurrent execution of a program. The child process is created by the chief process of a concurrent program.  The main process and child process need to interact with each other for completing the common task.

Feature of Process

  1. The process has process id, CPU registers, memory locations, stack.
  2. The process has its own virtual address space.
  3. It provides protected access to processors, other processes, files, and I/O.
  4. The process is a heavyweight.
  5. The creation of a process includes system calls for each process separately.
  6. A single process does not share data and information and takes its isolated memory space.
  7. The IPC (Inter-process communication) mechanism for communication is used by the processes, which significantly increases the number of system calls.
  8. More system calls are consumed by Process management.
  9. Every process contains the stack and heap memory, instruction, data, and memory map.

Thread

A thread is a lightweight process that shares the memory of a single process. It supports Multithreading. Each thread relates to exactly one process, and no thread can exist outside a process. Threads represent a software approach to improve the performance of the operating system. They also specify a suitable mechanism for parallel execution of applications on shared-memory multiprocessors. Threads are not independent of one another; that is why they share their code section, data section, and OS resources (like open files and signals) with each other. But a thread has its program counter (PC), register set, and stack space just like a process. The kernel provides a stack and a thread control block (TCB) to every thread. The Threads mainly have the states called the running, ready, and blocked states; it only includes computational state, not resource allocation, and communication state, which reduces the switching overhead. It enhances the concurrency (parallelism) because the many threads are the parts of the single process. So, each thread is assigned to do the task to speed up to complete the task.

When multiple threads are active, JVM provides the default priorities to each thread. The priority of the thread specifies the time available for execution relative to other active threads in the same process.

Feature of Thread:

  1. As a single process is executing for a single task, a thread may be part of the process, and it may execute a part of the process; hence it becomes the lightweight process. Thus, a single process may have many such threads that will take care of one part of the execution of that whole process. So, every thread that created or that is generated in a process also has its characteristics.
  2. Thread comprises a thread id, a program counter, a register set, and a stack as processes have process id, CPU registers, memory locations. The thread id is distinguished every thread.
  3. Threads share the resources of the process and are executing some part of the process
  4. Processes with threads are categories as following: The process may have the one or multithreaded.
  5. More than one thread (Lightweight process) is created by only one system call.
  6. Thread management does account for no or fewer system calls because communication between threads can be achieved using shared memory.

7. The process’s isolation property increases its overhead in terms of resource consumption.

Single-threaded

Single-threaded refers to executing an entire process from beginning to end without interruption by a single thread. Here, every process is associated with registers, stack, code, data, files, which is used by a single thread. This process contains a single thread that is executing only one work for a process at a time.

Process and Thread in Java2

For Example: If a web server is a single-threaded process, so web server will handle only a single request at a time, and all other users have to wait till this one request completed.

Multithreaded

Multithreaded refers to allowing multiple threads within a process so that they are executed independently while sharing their resources.

Here every thread will have its registers and stack that will store the information or store the work done by these particular threads in these registers and the stack.

Process and Thread in Java3

As this is the multithreaded process, the threads execute in the same resources that are being allotted to a process; hence multithreaded process or a thread is said to be the lightweight process as it does not require in additional resources to execute.

For example:

  1. In the Multithreaded web server, every thread will be assigned to each user, and every user will able to access the required information from the webserver.
  2. Similarly, the word processor will have a thread to access the data from the user simultaneously. Another thread will execute to find out the error, spelling mistakes that will be typed by the user, whereas other threads engage in the loading of the files, which are required in the word processor.

Benefits of Multithreaded over Single threaded:

Process and Thread in Java4

Responsiveness

By using Multithreading, it allows a program to run even if part of it is blocked. A program continuously runs also if the process is performing a lengthy operation.

As many threads execute simultaneously for any single process, it increases the responsiveness of a process as many threads doing the same job will improve the response of the process. In an interactive application, we allow the program to continue running even if a part is blocked or is performing some lengthy operation; still, the application will respond because of Multithreaded.

Resource sharing

 A single application can have many threads within the same address space for sharing the resources that are allocated to the process.

As threads are the parts of the same process, they share the memory and resource of the process to which they belong. The thread belongs to a specific process that is executing some instruction, so these allow the benefit of code sharing for an application so different threads may execute various activities for an application in the same address space.

Economy

To create processes relates to more expensive and time-consuming as they require more memory and resources as compared to threads. Management and creation are much higher than thread creation and management.

Every thread executes in the process to which it belongs. The threads do not have to allocate the new memory space or the resources, so they reduce the resource utilization of the operating system. There is not much more need for context switching between the processes as every thread is the part of the same process and executing a particular part of the process, so the context switching of the process is reduced, and that in turn reduces the resource requirement of any operating system. Thus, it removes the overhead for creating and maintaining a process rather than a thread.

Utilization of multiprocessor architectures

In this architecture, each thread can run on a different processor in parallel using multithreading. This increases the concurrency of the system. In contrast, a single processor system, where only one process or thread can run on a processor at a time.

We can utilize the full power of multiprocessor architectures where every thread can be assigned to a processor for some job. The multiple processors in the multiprocessor systems will execute one single job that may be part of a big processor, so this increases the speed of execution or speed of executing the processes highly by running parallel instructions on a different processor.

A Single-threaded process will run only on the one processor even there are many processors available for execution. In contrast, the Multithreaded process will utilize all the processors that are available in the system.

What is the difference between Process and the Thread?

Process Thread
The process is resource-intensive or heavyweight. Thread is taking lesser resources than a process and lightweight.
Process switching requires interaction with the operating system. The switching of the thread need not require to interact with the operating system.
All process has the same code but has its own private memory and file resources in multiple processing environments. All threads are sharing the same set of resources and open files of the processes.
There is no other process can execute until the first process is unblocked. If one thread is blocked and waiting, the other thread in the same task can run.
Without using threads, use more resources by the process. Multiple threaded processes use fewer resources.
Every process operates independently of the others. Threads are not independent among themselves as one thread can read, write, or change another thread’s data.

How does the Thread differ from the Process?

Faster context switch

A context switch occurs when the computer’s CPU switches(move) from a process or thread to a different process or thread. Context switching allows a CPU to handle multiple processes or threads without the need for additional processors. A (computer’s CPU) processor follows to change (switches) from one task to another while ensuring that tasks do not conflict.

Context switching involves storing the state or context of a process or thread so that it can be reloaded when the need arises, and execution can be resumed from the same point. This is the multitasking feature of the operating system and permits a single processor to be shared by multiple processes.

Context switching time between threads is lower compared to process context switch because threads relate to the shared memory as compared to the process. Process context switching consists of more overhead of the CPU as compared to threads context switching.

Communication

To communicate between multiple threads is easy as they share common address space (share memory). At the same time in the process, we have to follow some specific communication techniques (i.e., more system calls, etc.) for communication between processes because they do not share the memory space.

Enhanced throughput of the system

 In the Multithreading mechanism, each thread has a function that is considered as one job, then the number of jobs completed per unit of time is increased, thus increasing the throughput of the system.

Resource sharing

Among all threads within a process, share resources like code, data, and files. But the process does not share anything.

Effective utilization of multiprocessor system

If a single process has multiple threads, then we can schedule these threads on multiple processors. This mechanism will lead to process execution faster. But the complete process that are assigns to a processor takes time to finish according to its activity completion. The threads of-course increase the efficiency inside the process, but different processes complete after depends upon its activities to terminate.

Multitasking in Java

Multitasking is the mechanism in which a user performs more than one computer task at a time. The operating system can keep track of where you are in these tasks and go from one to the other without losing information. It is the way of executing several multiple tasks simultaneously. The operating systems which involve in the Multitasking are Microsoft Windows 2000, IBM ’s OS/390, and Linux.

Real-Life Example - classroom student is the best way of executing Multitasking.

  1. Students are listening to class.
  2. They are taking running notes of essential points.
  3. They are checking the mobile phone in the class by many students.
  4. They are observing the teacher’s way of teaching.

 Types of Multitasking

                  1. Process-based Multitasking

                  2. Thread-based Multitasking.

Process-based Multitasking: Executing several multiple tasks simultaneously, where each task is a separate independent program(process), is the process-based Multitasking.

Example –All these three activities will be performed simultaneously, and each task is independent of each other.

  1. Typing the java program in the editor
  2. Listening to the songs from the same system.
  3. Download a file from the internet.

While typing a java program in the editor, we can listen to audio songs from the same system at the same time we can download your file from the net. All these tasks will be executed simultaneously and independently of each other hence it is process-based Multitasking. It is better for the operating system level.

Thread based Multitasking:

It is the process of executing several tasks simultaneously where each task is a separate independent part of the same program. Such type of Multitasking is called Thread based Multitasking, and each independent part is called Thread. It is suitable for programming level 

Example: In a program, there are 10,000 lines of words. The first 5000 lines of code are independent to other 5000 lines of code that means first related to the first customer and second relates to another customer, so no need to wait to execute second customer lines of code after first lines of code. Both parts can be run simultaneously of the same program, so hardly less time to take to complete the execution. The first independent part and second independent part executing separate tasks simultaneously where each part is a separate independent part of the same program, and each independent task is Thread This type of Multitasking is Multithreading.

What is the difference between the Process and Thread based Multitasking?

Process-based Multitasking Thread-based Multitasking
Context switching is costing Context switching is not more costing
There is a separate address space for every process. Every thread shares one address space.
Each task is a separate independent process. Each task is the separate individual part of the same program.



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