Thread Introduction

  
A thread is a small independent executable code within a Program.

• A program can have multiple threads.
• Multiple thread can use the state of shared resources.
• Thread can be created by three ways
• 1) java.lang.Runnable Interface (since JDK 1.0)
• 2) java.util.concurrent.Callable Interface  (sice JDK 1.5)
• 3) java.lang.Thread class (since JDK 1.0)
• Each program is having a one thread. It is a main thread.
• Each thread is having a name and priority (1 to 10).
• Based on the priority each thread get a chance to utilize the CPU.
• By default thread inherits priority from its parent thread.
• Priority can also be set programmatically.
• Higher Priority thread get first chance.
• Similar priority thread get chance randomly. 
• Thread class has three priority constants
• public static int MIN_PRIORITY  ( 1)
• public static int NORM_PRIORITY (5)
• public static int MAX_PRIORITY (10)