Thread is the path of execution of a program..Types of 
threads are Single-threaded and Multi-threaded...This is 
mainly differentiated on the basis of synchronisation..A 
synchronised thread means a single thread executed only 
once at a time..Multithread means threads are executed 
simultaneously...

types of threads are daemon thread and non daemon thread.

that is one work in background like clock handler, and the 
one which we are used in the programs that is user defined 
threads.

2 type are

1.kernel thread
2.user thread

singlethread
multithread

we have three types of threads
1.User Define Thread(main Thread always execute first and 
start another thread)
2. Daemon thread (garbage Collection low priority thread)
3. GUI Thread( make as new create in main methods )