In java environment we have to introduce the multipart
program that executes simultaniously depending on the
priority called threads

Thread is block of code which can execute concurrently with 
other threads in JVM(Java Virtual Machine)

thread is a concept of java which help is help to tie the 
process one between another, also it give a new one called 
multiple process run in same time called multi threading....

Thread is a path of execution of a program and java 
supports multi-thread programming

thread is a light wieght processor.

Thread is a class which extends Thread class or Implements 
Runnable Interface.
Thread can run as an Independant process than current 
Excecution steps. The Main thread that runs always is known 
as CurrentThread accessed by Thread.currentThread();
Only one thread can access CPU time ( JVM then CPU). Multi 
thread mechanisum is possible by making several threads in 
waiting state and running only one at a time.

JVM assign priorities for every threads and accesses in a 
Time Slicing / scheduled way considering the OS.

Defauls is normal.

Every object is like a Football to threads. hence Every 
object must have methods to handle a thread. All the 
players may be running in the field but only one player can 
handle the Ball at a time. Object have methods like wait(), 
notify() notifyAll() etc to catch and release the working 
thread.

If you do not want a ball to change shape once it is 
accessed by a thread then you need to synchronise the 
statements or methods. Once synchronized the thread which 
is the owner of the Object can only change the state of the 
object.
//Method
public void synchronized x(){
 }

//statement 
synchronized (x);

Thread is a process of execution of work.
 In a java application ,the thread starts when the 
main() starts executing till the whole Application is 
executed.
 Java supports multi threading,Multi threading is a concept 
where more than one thread can be used in a program while 
executing the applicaton.

thread is a sequential execution flow of control

Thread is a part of a program that is in Execution.
It is a Light weight process.

Thread is a unit of program code in execution. It is unit of
dispatching.
Thread can be viewed as an independent program counter
within a process.
Basically it reduces switching overhead and helps
multiprogramming.