Easy approach to learn Threads

How to create a Thread?

Why Runnable is preferred over Thread?

  1. In OOPS, we extend the class to add new functionality, modify or improve functionality. If you are not making any modification on Thread functionality then we should go for Runnable Interface instead.
  2. Runnable represent a task. It can be executed by either plain Thread or Executor. With Runnable, we are separating the task from execution which is a flexible design.
  3. By extending the Thread, we have the overhead of inheriting all the Thread methods.

How to pause a thread?

How to interrupt a thread?

How to fetch the output from a Thread?

How do threads communicate?

How to protect shared data when it is accessed by multiple threads?

How to achieve thread safety?

  1. Minimize the sharing of objects between multiple threads.
  2. In case if the object is shared between multiple threads, multiple access should be restricted on the shared object. synchronize/Lock the shared object calls to ensure single access to the shared resource at any given point in time.
  3. Using immutable classes in multi-threaded environments is the best approach since the state of these instances cannot be changed.

Why Thread pool is better than a thread?

  1. Creation of thread is a costly process. Because it consumes time, CPU process (because OS has to create a separate process for the thread creation), and there is a limit on no. of threads created per JVM. So, creating a thread for a task is costlier than picking an already created thread from the thread pool.
  2. If we use a thread pool, we can reuse the fixed set of Threads(value of no. of threads is very much bounded) to do the tasks. Whereas in Threads, we have to create a thread for every incoming task which is unbounded.
  3. Thread pool uses threads which are already created. So, the task completion time is much quicker when compared to Thread.

How to create, manage Thread pools in Java?



Comments

Post a Comment

Popular posts from this blog

Distributed database design using CAP theorem

Image
CAP is a theorem/standard which can be applied while designing distributed systems like distributed databases. A distributed database is a set of databases(nodes) which are spread across the network.  These set of databases(nodes) in the distributed database can be either designed as either a  master/slave  or a  sharded model . Consistency -  Database should return the latest write on the DB. Availability -  Database should return data in a decent amount of time .  But, the data might not be latest. Partition tolerant - I n spite of n/w failure, the database should always be available. A distributed database can be designed either as a CP, AP, CA but not with all the 3 capabilities.  AP - Available and Partition tolerant  -  Sharded model (Data is distributed, No Master)  -      Availability  - Because, the data is distributed, any of the nodes can return the data. So, always availabl...
Continue Reading »

SQL Analytical Functions - Partition by (to split resultset into groups)

Partition by:  Splits the resultset into groups.  Employees -Table EMPLOYEE_ID FIRST_NAME SALARY ----------- -------------------- ---------- 100 Steven 24000 101 Neena 17000 102 Lex 17000 103 Alexander 9000 104 Bruce 6000 105 David 4800 106 Valli 4800 107 Diana 4200 select e.employee_id, e.department_id, salary, row_number() over (partition by department_id order by salary desc) as rownumber from employees e; The above query splits the result into small subgroups for every department.  Syntax :  Function(arg1,..., argn) OVER ( [PARTITION BY <..>] [ORDER BY <....>]  [<window_clause>] ) partition by  - create  subgroups for e...
Continue Reading »

Easy approach to work with files in Java - Java NIO(New input output)

  NIO - New IO package. Introduced in 1.4. It is buffer based and non-blocking. Hence, faster than IO package. It supports symbolic links, posix file attributes(works only on OS's which are POSIX compliant), ACL (Access control list). Paths and Files are the main classes Creating a potential file reference: Path path = Paths.get("c:/demo/"); //possible file reference Creating a directory, file, write to the file, read from the file: //create all the non existing directories in the path. Ignores creating a directory, if that directory already exists Path directories = Files.createDirectories("c:/demo/example1/properties/"); Path newFilePath = Files.createFile("c:/demo/README.txt"); //Creating a file //Writting bytes to the file Files.write(newFilePath, "This is a dummy text".getBytes(StandardCharsets.UTF_8)); //Reading bytes from file String readFile = new String(Files.readAllBytes(newFilePath), "UTF-8"); Files.readAllBytes reads all...
Continue Reading »