Control the boot order of two threads

The interview encountered such a problem: threads A and thread B, how to control thread B in line a start 3 seconds or after thread a runs to start?

The topic shows that thread B's start-up time is to meet two conditions:

1. After thread a starts 3 seconds

2. After the end of thread a runs

This means that as long as the above two conditions have a satisfying, thread B will start.

Use Countdownlatch to control call timing, the code is as follows:

1  Public classRunAImplementsRunnable {2     PrivateCountdownlatch CDL;3      PublicRunA (Countdownlatch CDL) {4          This. CDL =CDL;5     }6 @Override7      Public voidrun () {8         //TODO auto-generated Method Stub9         Try {TenThread.Sleep (1000); One Cdl.countdown (); ASystem.out.println ("A run Over"); -}Catch(interruptedexception e) { -             //TODO auto-generated Catch block the e.printstacktrace (); -         } -     } -}

1  Public classRunbImplementsRunnable {2     PrivateCountdownlatch CDL;3      PublicRunb (Countdownlatch CDL) {4          This. CDL =CDL;5     }6 @Override7      Public voidrun () {8         //TODO auto-generated Method Stub9         Try {TenCdl.await (3000, timeunit.milliseconds); OneSystem.out.println ("B run Over"); A}Catch(interruptedexception e) { -             //TODO auto-generated Catch block - e.printstacktrace (); the         } -     } -}

1  Public classTest {2      Public Static voidMain (string[] args) {3Countdownlatch CDL =NewCountdownlatch (1);4Thread TA =NewThread (NewRunA (CDL));5Thread TB =NewThread (NewRunb (CDL));6 Ta.start ();7 Tb.start ();8     }9}

Control the boot order of two threads