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How to understand ` catch up` of Java Timer `scheduleAtFixedRate` method and `schedule` method actual run...
1
java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, long, long) the doc say:
If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up."
And I do a test, code as follow:
public static void main(String args) {
Timer timer = new Timer();
TimerTask timerTask = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 实际运行时间：%s,需要运行时间：%s", new Date(), new Date(this.scheduledExecutionTime())));
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
TimerTask timerTask1 = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 1 实际运行时间：%s,需要运行时间：%s", new Date().getTime(), new Date(this.scheduledExecutionTime())));
}
};
System.out.println("开始执行时间：" + new Date());
timer.schedule(timerTask, 0, 1000);//
timer.scheduleAtFixedRate(timerTask1, 0, 1000);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
an example of results:
开始执行时间：Tue Nov 20 15:56:50 CST 2018 --line 1
Task 实际运行时间：Tue Nov 20 15:56:50 CST 2018,需要运行时间：Tue Nov 20 15:56:50 CST 2018 --line 2
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:50 CST 2018,计时器：1 --line 3
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:51 CST 2018,计时器：2 --line 4
Task 实际运行时间：Tue Nov 20 15:56:53 CST 2018,需要运行时间：Tue Nov 20 15:56:53 CST 2018 --line 5
line 3,4 实际运行时间 is same time,and how to understand the catch up upon the method doc?
line 2,5 The Task run time need at less 3 second,and period is 1 second ,and the console why not per 1 second?
java
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
add a comment |
1
java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, long, long) the doc say:
If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up."
And I do a test, code as follow:
public static void main(String args) {
Timer timer = new Timer();
TimerTask timerTask = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 实际运行时间：%s,需要运行时间：%s", new Date(), new Date(this.scheduledExecutionTime())));
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
TimerTask timerTask1 = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 1 实际运行时间：%s,需要运行时间：%s", new Date().getTime(), new Date(this.scheduledExecutionTime())));
}
};
System.out.println("开始执行时间：" + new Date());
timer.schedule(timerTask, 0, 1000);//
timer.scheduleAtFixedRate(timerTask1, 0, 1000);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
an example of results:
开始执行时间：Tue Nov 20 15:56:50 CST 2018 --line 1
Task 实际运行时间：Tue Nov 20 15:56:50 CST 2018,需要运行时间：Tue Nov 20 15:56:50 CST 2018 --line 2
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:50 CST 2018,计时器：1 --line 3
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:51 CST 2018,计时器：2 --line 4
Task 实际运行时间：Tue Nov 20 15:56:53 CST 2018,需要运行时间：Tue Nov 20 15:56:53 CST 2018 --line 5
line 3,4 实际运行时间 is same time,and how to understand the catch up upon the method doc?
line 2,5 The Task run time need at less 3 second,and period is 1 second ,and the console why not per 1 second?
java
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
It doesn't answer your question but aTimerTaskshould be fast in order to maintain the scheduling. In other words, it should not take seconds. In case your task has a lot of work to do, create a new thread within therunmethod of your timertask.
– Robert Kock
Nov 20 '18 at 9:31
@Robert Kock ,thank you for your reply，I agree with your opinion.
– zhiwen zhang
Nov 21 '18 at 7:19
add a comment |
1
1
1
java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, long, long) the doc say:
If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up."
And I do a test, code as follow:
public static void main(String args) {
Timer timer = new Timer();
TimerTask timerTask = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 实际运行时间：%s,需要运行时间：%s", new Date(), new Date(this.scheduledExecutionTime())));
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
TimerTask timerTask1 = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 1 实际运行时间：%s,需要运行时间：%s", new Date().getTime(), new Date(this.scheduledExecutionTime())));
}
};
System.out.println("开始执行时间：" + new Date());
timer.schedule(timerTask, 0, 1000);//
timer.scheduleAtFixedRate(timerTask1, 0, 1000);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
an example of results:
开始执行时间：Tue Nov 20 15:56:50 CST 2018 --line 1
Task 实际运行时间：Tue Nov 20 15:56:50 CST 2018,需要运行时间：Tue Nov 20 15:56:50 CST 2018 --line 2
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:50 CST 2018,计时器：1 --line 3
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:51 CST 2018,计时器：2 --line 4
Task 实际运行时间：Tue Nov 20 15:56:53 CST 2018,需要运行时间：Tue Nov 20 15:56:53 CST 2018 --line 5
line 3,4 实际运行时间 is same time,and how to understand the catch up upon the method doc?
line 2,5 The Task run time need at less 3 second,and period is 1 second ,and the console why not per 1 second?
java
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, long, long) the doc say:
If an execution is delayed for any reason (such as garbage collection or other background activity), two or more executions will occur in rapid succession to "catch up."
And I do a test, code as follow:
public static void main(String args) {
Timer timer = new Timer();
TimerTask timerTask = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 实际运行时间：%s,需要运行时间：%s", new Date(), new Date(this.scheduledExecutionTime())));
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
TimerTask timerTask1 = new TimerTask() {
@Override
public void run() {
System.out.println(String.format("Task 1 实际运行时间：%s,需要运行时间：%s", new Date().getTime(), new Date(this.scheduledExecutionTime())));
}
};
System.out.println("开始执行时间：" + new Date());
timer.schedule(timerTask, 0, 1000);//
timer.scheduleAtFixedRate(timerTask1, 0, 1000);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
an example of results:
开始执行时间：Tue Nov 20 15:56:50 CST 2018 --line 1
Task 实际运行时间：Tue Nov 20 15:56:50 CST 2018,需要运行时间：Tue Nov 20 15:56:50 CST 2018 --line 2
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:50 CST 2018,计时器：1 --line 3
Task 1 实际运行时间：1542700613673,需要运行时间：Tue Nov 20 15:56:51 CST 2018,计时器：2 --line 4
Task 实际运行时间：Tue Nov 20 15:56:53 CST 2018,需要运行时间：Tue Nov 20 15:56:53 CST 2018 --line 5
line 3,4 实际运行时间 is same time,and how to understand the catch up upon the method doc?
line 2,5 The Task run time need at less 3 second,and period is 1 second ,and the console why not per 1 second?
java
java
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
edited Nov 20 '18 at 7:58
zhiwen zhang
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
asked Nov 20 '18 at 7:45
zhiwen zhangzhiwen zhang
208419
208419
It doesn't answer your question but aTimerTaskshould be fast in order to maintain the scheduling. In other words, it should not take seconds. In case your task has a lot of work to do, create a new thread within therunmethod of your timertask.
– Robert Kock
Nov 20 '18 at 9:31
@Robert Kock ,thank you for your reply，I agree with your opinion.
– zhiwen zhang
Nov 21 '18 at 7:19
add a comment |
It doesn't answer your question but aTimerTaskshould be fast in order to maintain the scheduling. In other words, it should not take seconds. In case your task has a lot of work to do, create a new thread within therunmethod of your timertask.
– Robert Kock
Nov 20 '18 at 9:31
@Robert Kock ,thank you for your reply，I agree with your opinion.
– zhiwen zhang
Nov 21 '18 at 7:19
It doesn't answer your question but a
TimerTask should be fast in order to maintain the scheduling. In other words, it should not take seconds. In case your task has a lot of work to do, create a new thread within the run method of your timertask.– Robert Kock
Nov 20 '18 at 9:31
It doesn't answer your question but a
TimerTask should be fast in order to maintain the scheduling. In other words, it should not take seconds. In case your task has a lot of work to do, create a new thread within the run method of your timertask.– Robert Kock
Nov 20 '18 at 9:31
@Robert Kock ,thank you for your reply，I agree with your opinion.
– zhiwen zhang
Nov 21 '18 at 7:19
@Robert Kock ,thank you for your reply，I agree with your opinion.
– zhiwen zhang
Nov 21 '18 at 7:19
add a comment |
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It doesn't answer your question but a
TimerTaskshould be fast in order to maintain the scheduling. In other words, it should not take seconds. In case your task has a lot of work to do, create a new thread within therunmethod of your timertask.– Robert Kock
Nov 20 '18 at 9:31
@Robert Kock ,thank you for your reply，I agree with your opinion.
– zhiwen zhang
Nov 21 '18 at 7:19