We Keep Coding

Repeating task with handler take more time than interval

I get my data from the server and have to update it every x seconds.
I do this using the Handler's postDelayed function.
private long mInterval = 10000;
Runnable mStatusChecker = new Runnable() {
#Override
public void run() {
try {
takeServerResponse(); //with vary duration
}catch (Exception e){
itsRunning = false;
} finally {
if(mHandler!=null) {
mHandler.postDelayed(mStatusChecker, mInterval);
}
}
}
};
Sometimes it may take more than X seconds to get new data.
What can I do in this situation?
If we need increase interval,how to determine when to do so?

You can calculate the duration time of your job and postDelayed your handler based on the duration time.
For example:
startTime = System.currentTimeMillis();
//your job
duration = System.currentTimeMillis() - startTime;
mInterval = mInterval - duration

your handler used to call the server response after 10 sec.But Its all depend own your internet speed to get the data from server that's the reason its take long time

how calculate running time of method containing other method using new Date().getTime() in java? [duplicate]

How do I get a method's execution time?
Is there a Timer utility class for things like timing how long a task takes, etc?
Most of the searches on Google return results for timers that schedule threads and tasks, which is not what I want.

There is always the old-fashioned way:
long startTime = System.nanoTime();
methodToTime();
long endTime = System.nanoTime();
long duration = (endTime - startTime); //divide by 1000000 to get milliseconds.

I go with the simple answer. Works for me.
long startTime = System.currentTimeMillis();
doReallyLongThing();
long endTime = System.currentTimeMillis();
System.out.println("That took " + (endTime - startTime) + " milliseconds");
It works quite well. The resolution is obviously only to the millisecond, you can do better with System.nanoTime(). There are some limitations to both (operating system schedule slices, etc.) but this works pretty well.
Average across a couple of runs (the more the better) and you'll get a decent idea.

Come on guys! Nobody mentioned the Guava way to do that (which is arguably awesome):
import com.google.common.base.Stopwatch;
Stopwatch timer = Stopwatch.createStarted();
//method invocation
LOG.info("Method took: " + timer.stop());
The nice thing is that Stopwatch.toString() does a good job of selecting time units for the measurement. I.e. if the value is small, it'll output 38 ns, if it's long, it'll show 5m 3s
Even nicer:
Stopwatch timer = Stopwatch.createUnstarted();
for (...) {
timer.start();
methodToTrackTimeFor();
timer.stop();
methodNotToTrackTimeFor();
}
LOG.info("Method took: " + timer);
Note: Google Guava requires Java 1.6+

Using Instant and Duration from Java 8's new API,
Instant start = Instant.now();
Thread.sleep(5000);
Instant end = Instant.now();
System.out.println(Duration.between(start, end));
outputs,
PT5S

Gathered all possible ways together into one place.
Date
Date startDate = Calendar.getInstance().getTime();
long d_StartTime = new Date().getTime();
Thread.sleep(1000 * 4);
Date endDate = Calendar.getInstance().getTime();
long d_endTime = new Date().getTime();
System.out.format("StartDate : %s, EndDate : %s \n", startDate, endDate);
System.out.format("Milli = %s, ( D_Start : %s, D_End : %s ) \n", (d_endTime - d_StartTime),d_StartTime, d_endTime);
System.currentTimeMillis()
long startTime = System.currentTimeMillis();
Thread.sleep(1000 * 4);
long endTime = System.currentTimeMillis();
long duration = (endTime - startTime);
System.out.format("Milli = %s, ( S_Start : %s, S_End : %s ) \n", duration, startTime, endTime );
System.out.println("Human-Readable format : "+millisToShortDHMS( duration ) );
Human Readable Format
public static String millisToShortDHMS(long duration) {
String res = ""; // java.util.concurrent.TimeUnit;
long days = TimeUnit.MILLISECONDS.toDays(duration);
long hours = TimeUnit.MILLISECONDS.toHours(duration) -
TimeUnit.DAYS.toHours(TimeUnit.MILLISECONDS.toDays(duration));
long minutes = TimeUnit.MILLISECONDS.toMinutes(duration) -
TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(duration));
long seconds = TimeUnit.MILLISECONDS.toSeconds(duration) -
TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(duration));
long millis = TimeUnit.MILLISECONDS.toMillis(duration) -
TimeUnit.SECONDS.toMillis(TimeUnit.MILLISECONDS.toSeconds(duration));
if (days == 0) res = String.format("%02d:%02d:%02d.%04d", hours, minutes, seconds, millis);
else res = String.format("%dd %02d:%02d:%02d.%04d", days, hours, minutes, seconds, millis);
return res;
}
Guava: Google StopwatchJAR « An object of Stopwatch is to measures elapsed time in nanoseconds.
com.google.common.base.Stopwatch g_SW = Stopwatch.createUnstarted();
g_SW.start();
Thread.sleep(1000 * 4);
g_SW.stop();
System.out.println("Google StopWatch : "+g_SW);
Apache Commons LangJAR
« StopWatch provides a convenient API for timings.
org.apache.commons.lang3.time.StopWatch sw = new StopWatch();
sw.start();
Thread.sleep(1000 * 4);
sw.stop();
System.out.println("Apache StopWatch : "+ millisToShortDHMS(sw.getTime()) );
JODA-TIME
public static void jodaTime() throws InterruptedException, ParseException{
java.text.SimpleDateFormat ms_SDF = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS");
String start = ms_SDF.format( new Date() ); // java.util.Date
Thread.sleep(10000);
String end = ms_SDF.format( new Date() );
System.out.println("Start:"+start+"\t Stop:"+end);
Date date_1 = ms_SDF.parse(start);
Date date_2 = ms_SDF.parse(end);
Interval interval = new org.joda.time.Interval( date_1.getTime(), date_2.getTime() );
Period period = interval.toPeriod(); //org.joda.time.Period
System.out.format("%dY/%dM/%dD, %02d:%02d:%02d.%04d \n",
period.getYears(), period.getMonths(), period.getDays(),
period.getHours(), period.getMinutes(), period.getSeconds(), period.getMillis());
}
Java date time API from Java 8 « A Duration object represents a period of time between two Instant objects.
Instant start = java.time.Instant.now();
Thread.sleep(1000);
Instant end = java.time.Instant.now();
Duration between = java.time.Duration.between(start, end);
System.out.println( between ); // PT1.001S
System.out.format("%dD, %02d:%02d:%02d.%04d \n", between.toDays(),
between.toHours(), between.toMinutes(), between.getSeconds(), between.toMillis()); // 0D, 00:00:01.1001
Spring Framework provides StopWatch utility class to measure elapsed time in Java.
StopWatch sw = new org.springframework.util.StopWatch();
sw.start("Method-1"); // Start a named task
Thread.sleep(500);
sw.stop();
sw.start("Method-2");
Thread.sleep(300);
sw.stop();
sw.start("Method-3");
Thread.sleep(200);
sw.stop();
System.out.println("Total time in milliseconds for all tasks :\n"+sw.getTotalTimeMillis());
System.out.println("Table describing all tasks performed :\n"+sw.prettyPrint());
System.out.format("Time taken by the last task : [%s]:[%d]",
sw.getLastTaskName(),sw.getLastTaskTimeMillis());
System.out.println("\n Array of the data for tasks performed « Task Name: Time Taken");
TaskInfo[] listofTasks = sw.getTaskInfo();
for (TaskInfo task : listofTasks) {
System.out.format("[%s]:[%d]\n",
task.getTaskName(), task.getTimeMillis());
}
OutPut:
Total time in milliseconds for all tasks :
999
Table describing all tasks performed :
StopWatch '': running time (millis) = 999
-----------------------------------------
ms % Task name
-----------------------------------------
00500 050% Method-1
00299 030% Method-2
00200 020% Method-3
Time taken by the last task : [Method-3]:[200]
Array of the data for tasks performed « Task Name: Time Taken
[Method-1]:[500]
[Method-2]:[299]
[Method-3]:[200]

Use a profiler (JProfiler, Netbeans Profiler, Visual VM, Eclipse Profiler, etc). You'll get the most accurate results and is the least intrusive. They use the built-in JVM mechanism for profiling which can also give you extra information like stack traces, execution paths, and more comprehensive results if necessary.
When using a fully integrated profiler, it's faily trivial to profile a method. Right click, Profiler -> Add to Root Methods. Then run the profiler just like you were doing a test run or debugger.

System.currentTimeMillis(); IS NOT a good approach for measuring the performance of your algorithms. It measures the total time you experience as a user watching the computer screen. It includes also time consumed by everything else running on your computer in the background. This could make a huge difference in case you have a lot of programs running on your workstation.
Proper approach is using java.lang.management package.
From http://nadeausoftware.com/articles/2008/03/java_tip_how_get_cpu_and_user_time_benchmarking website (archive link):
"User time" is the time spent running your application's own code.
"System time" is the time spent running OS code on behalf of your application (such as for I/O).
getCpuTime() method gives you sum of those:
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;
public class CPUUtils {
/** Get CPU time in nanoseconds. */
public static long getCpuTime( ) {
ThreadMXBean bean = ManagementFactory.getThreadMXBean( );
return bean.isCurrentThreadCpuTimeSupported( ) ?
bean.getCurrentThreadCpuTime( ) : 0L;
}
/** Get user time in nanoseconds. */
public static long getUserTime( ) {
ThreadMXBean bean = ManagementFactory.getThreadMXBean( );
return bean.isCurrentThreadCpuTimeSupported( ) ?
bean.getCurrentThreadUserTime( ) : 0L;
}
/** Get system time in nanoseconds. */
public static long getSystemTime( ) {
ThreadMXBean bean = ManagementFactory.getThreadMXBean( );
return bean.isCurrentThreadCpuTimeSupported( ) ?
(bean.getCurrentThreadCpuTime( ) - bean.getCurrentThreadUserTime( )) : 0L;
}
}

This probably isn't what you wanted me to say, but this is a good use of AOP. Whip an proxy interceptor around your method, and do the timing in there.
The what, why and how of AOP is rather beyond the scope of this answer, sadly, but that's how I'd likely do it.
Edit: Here's a link to Spring AOP to get you started, if you're keen. This is the most accessible implementation of AOP that Iive come across for java.
Also, given everyone else's very simple suggestions, I should add that AOP is for when you don't want stuff like timing to invade your code. But in many cases, that sort of simple and easy approach is fine.

With Java 8 you can do also something like this with every normal methods:
Object returnValue = TimeIt.printTime(() -> methodeWithReturnValue());
//do stuff with your returnValue
with TimeIt like:
public class TimeIt {
public static <T> T printTime(Callable<T> task) {
T call = null;
try {
long startTime = System.currentTimeMillis();
call = task.call();
System.out.print((System.currentTimeMillis() - startTime) / 1000d + "s");
} catch (Exception e) {
//...
}
return call;
}
}
With this methode you can make easy time measurement anywhere in your code without breaking it. In this simple example i just print the time. May you add a Switch for TimeIt, e.g. to only print the time in DebugMode or something.
If you are working with Function you can do somthing like this:
Function<Integer, Integer> yourFunction= (n) -> {
return IntStream.range(0, n).reduce(0, (a, b) -> a + b);
};
Integer returnValue = TimeIt.printTime2(yourFunction).apply(10000);
//do stuff with your returnValue
public static <T, R> Function<T, R> printTime2(Function<T, R> task) {
return (t) -> {
long startTime = System.currentTimeMillis();
R apply = task.apply(t);
System.out.print((System.currentTimeMillis() - startTime) / 1000d
+ "s");
return apply;
};
}

Also We can use StopWatch class of Apache commons for measuring the time.
Sample code
org.apache.commons.lang.time.StopWatch sw = new org.apache.commons.lang.time.StopWatch();
System.out.println("getEventFilterTreeData :: Start Time : " + sw.getTime());
sw.start();
// Method execution code
sw.stop();
System.out.println("getEventFilterTreeData :: End Time : " + sw.getTime());

JEP 230: Microbenchmark Suite
FYI, JEP 230: Microbenchmark Suite is an OpenJDK project to:
Add a basic suite of microbenchmarks to the JDK source code, and make it easy for developers to run existing microbenchmarks and create new ones.
This feature arrived in Java 12.
Java Microbenchmark Harness (JMH)
For earlier versions of Java, take a look at the Java Microbenchmark Harness (JMH) project on which JEP 230 is based.

Just a small twist, if you don't use tooling and want to time methods with low execution time: execute it many times, each time doubling the number of times it is executed until you reach a second, or so. Thus, the time of the Call to System.nanoTime and so forth, nor the accuracy of System.nanoTime does affect the result much.
int runs = 0, runsPerRound = 10;
long begin = System.nanoTime(), end;
do {
for (int i=0; i<runsPerRound; ++i) timedMethod();
end = System.nanoTime();
runs += runsPerRound;
runsPerRound *= 2;
} while (runs < Integer.MAX_VALUE / 2 && 1000000000L > end - begin);
System.out.println("Time for timedMethod() is " +
0.000000001 * (end-begin) / runs + " seconds");
Of course, the caveats about using the wall clock apply: influences of JIT-compilation, multiple threads / processes etc. Thus, you need to first execute the method a lot of times first, such that the JIT compiler does its work, and then repeat this test multiple times and take the lowest execution time.

We are using AspectJ and Java annotations for this purpose. If we need to know to execution time for a method, we simple annotate it. A more advanced version could use an own log level that can enabled and disabled at runtime.
public #interface Trace {
boolean showParameters();
}
#Aspect
public class TraceAspect {
[...]
#Around("tracePointcut() && #annotation(trace) && !within(TraceAspect)")
public Object traceAdvice ( ProceedingJintPoint jP, Trace trace ) {
Object result;
// initilize timer
try {
result = jp.procced();
} finally {
// calculate execution time
}
return result;
}
[...]
}

Really good code.
http://www.rgagnon.com/javadetails/java-0585.html
import java.util.concurrent.TimeUnit;
long startTime = System.currentTimeMillis();
........
........
........
long finishTime = System.currentTimeMillis();
String diff = millisToShortDHMS(finishTime - startTime);
/**
* converts time (in milliseconds) to human-readable format
* "<dd:>hh:mm:ss"
*/
public static String millisToShortDHMS(long duration) {
String res = "";
long days = TimeUnit.MILLISECONDS.toDays(duration);
long hours = TimeUnit.MILLISECONDS.toHours(duration)
- TimeUnit.DAYS.toHours(TimeUnit.MILLISECONDS.toDays(duration));
long minutes = TimeUnit.MILLISECONDS.toMinutes(duration)
- TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(duration));
long seconds = TimeUnit.MILLISECONDS.toSeconds(duration)
- TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(duration));
if (days == 0) {
res = String.format("%02d:%02d:%02d", hours, minutes, seconds);
}
else {
res = String.format("%dd%02d:%02d:%02d", days, hours, minutes, seconds);
}
return res;
}

Spring provides a utility class org.springframework.util.StopWatch, as per JavaDoc:
Simple stop watch, allowing for timing of a number of tasks, exposing
total running time and running time for each named task.
Usage:
StopWatch stopWatch = new StopWatch("Performance Test Result");
stopWatch.start("Method 1");
doSomething1();//method to test
stopWatch.stop();
stopWatch.start("Method 2");
doSomething2();//method to test
stopWatch.stop();
System.out.println(stopWatch.prettyPrint());
Output:
StopWatch 'Performance Test Result': running time (millis) = 12829
-----------------------------------------
ms % Task name
-----------------------------------------
11907 036% Method 1
00922 064% Method 2
With Aspects:
#Around("execution(* my.package..*.*(..))")
public Object logTime(ProceedingJoinPoint joinPoint) throws Throwable {
StopWatch stopWatch = new StopWatch();
stopWatch.start();
Object retVal = joinPoint.proceed();
stopWatch.stop();
log.info(" execution time: " + stopWatch.getTotalTimeMillis() + " ms");
return retVal;
}

You can use Perf4j. Very cool utility. Usage is simple
String watchTag = "target.SomeMethod";
StopWatch stopWatch = new LoggingStopWatch(watchTag);
Result result = null; // Result is a type of a return value of a method
try {
result = target.SomeMethod();
stopWatch.stop(watchTag + ".success");
} catch (Exception e) {
stopWatch.stop(watchTag + ".fail", "Exception was " + e);
throw e;
}
More information can be found in Developer Guide
Edit: Project seems dead

I have written a method to print the method execution time in a much readable form.
For example, to calculate the factorial of 1 Million, it takes approximately 9 minutes. So the execution time get printed as:
Execution Time: 9 Minutes, 36 Seconds, 237 MicroSeconds, 806193 NanoSeconds
The code is here:
public class series
{
public static void main(String[] args)
{
long startTime = System.nanoTime();
long n = 10_00_000;
printFactorial(n);
long endTime = System.nanoTime();
printExecutionTime(startTime, endTime);
}
public static void printExecutionTime(long startTime, long endTime)
{
long time_ns = endTime - startTime;
long time_ms = TimeUnit.NANOSECONDS.toMillis(time_ns);
long time_sec = TimeUnit.NANOSECONDS.toSeconds(time_ns);
long time_min = TimeUnit.NANOSECONDS.toMinutes(time_ns);
long time_hour = TimeUnit.NANOSECONDS.toHours(time_ns);
System.out.print("\nExecution Time: ");
if(time_hour > 0)
System.out.print(time_hour + " Hours, ");
if(time_min > 0)
System.out.print(time_min % 60 + " Minutes, ");
if(time_sec > 0)
System.out.print(time_sec % 60 + " Seconds, ");
if(time_ms > 0)
System.out.print(time_ms % 1E+3 + " MicroSeconds, ");
if(time_ns > 0)
System.out.print(time_ns % 1E+6 + " NanoSeconds");
}
}

In Spring framework we have a call called StopWatch (org.springframework.util.StopWatch)
//measuring elapsed time using Spring StopWatch
StopWatch watch = new StopWatch();
watch.start();
for(int i=0; i< 1000; i++){
Object obj = new Object();
}
watch.stop();
System.out.println("Total execution time to create 1000 objects in Java using StopWatch in millis: "
+ watch.getTotalTimeMillis());

new Timer(""){{
// code to time
}}.timeMe();
public class Timer {
private final String timerName;
private long started;
public Timer(String timerName) {
this.timerName = timerName;
this.started = System.currentTimeMillis();
}
public void timeMe() {
System.out.println(
String.format("Execution of '%s' takes %dms.",
timerName,
started-System.currentTimeMillis()));
}
}

Using AOP/AspectJ and #Loggable annotation from jcabi-aspects you can do it easy and compact:
#Loggable(Loggable.DEBUG)
public String getSomeResult() {
// return some value
}
Every call to this method will be sent to SLF4J logging facility with DEBUG logging level. And every log message will include execution time.

You can use Metrics library which provides various measuring instruments. Add dependency:
<dependencies>
<dependency>
<groupId>io.dropwizard.metrics</groupId>
<artifactId>metrics-core</artifactId>
<version>${metrics.version}</version>
</dependency>
</dependencies>
And configure it for your environment.
Methods can be annotated with #Timed:
#Timed
public void exampleMethod(){
// some code
}
or piece of code wrapped with Timer:
final Timer timer = metricsRegistry.timer("some_name");
final Timer.Context context = timer.time();
// timed code
context.stop();
Aggregated metrics can exported to console, JMX, CSV or other.
#Timed metrics output example:
com.example.ExampleService.exampleMethod
count = 2
mean rate = 3.11 calls/minute
1-minute rate = 0.96 calls/minute
5-minute rate = 0.20 calls/minute
15-minute rate = 0.07 calls/minute
min = 17.01 milliseconds
max = 1006.68 milliseconds
mean = 511.84 milliseconds
stddev = 699.80 milliseconds
median = 511.84 milliseconds
75% <= 1006.68 milliseconds
95% <= 1006.68 milliseconds
98% <= 1006.68 milliseconds
99% <= 1006.68 milliseconds
99.9% <= 1006.68 milliseconds

I basically do variations of this, but considering how hotspot compilation works, if you want to get accurate results you need to throw out the first few measurements and make sure you are using the method in a real world (read application specific) application.
If the JIT decides to compile it your numbers will vary heavily. so just be aware

There are a couple of ways to do that. I normally fall back to just using something like this:
long start = System.currentTimeMillis();
// ... do something ...
long end = System.currentTimeMillis();
or the same thing with System.nanoTime();
For something more on the benchmarking side of things there seems also to be this one: http://jetm.void.fm/ Never tried it though.

If you want wall-clock time
long start_time = System.currentTimeMillis();
object.method();
long end_time = System.currentTimeMillis();
long execution_time = end_time - start_time;

As "skaffman" said, use AOP OR you can use run time bytecode weaving, just like unit test method coverage tools use to transparently add timing info to methods invoked.
You can look at code used by open source tools tools like Emma (http://downloads.sourceforge.net/emma/emma-2.0.5312-src.zip?modtime=1118607545&big_mirror=0). The other opensource coverage tool is http://prdownloads.sourceforge.net/cobertura/cobertura-1.9-src.zip?download.
If you eventually manage to do what you set out for, pls. share it back with the community here with your ant task/jars.

long startTime = System.currentTimeMillis();
// code goes here
long finishTime = System.currentTimeMillis();
long elapsedTime = finishTime - startTime; // elapsed time in milliseconds

I modified the code from correct answer to get result in seconds:
long startTime = System.nanoTime();
methodCode ...
long endTime = System.nanoTime();
double duration = (double)(endTime - startTime) / (Math.pow(10, 9));
Log.v(TAG, "MethodName time (s) = " + duration);

Ok, this is a simple class to be used for simple simple timing of your functions. There is an example below it.
public class Stopwatch {
static long startTime;
static long splitTime;
static long endTime;
public Stopwatch() {
start();
}
public void start() {
startTime = System.currentTimeMillis();
splitTime = System.currentTimeMillis();
endTime = System.currentTimeMillis();
}
public void split() {
split("");
}
public void split(String tag) {
endTime = System.currentTimeMillis();
System.out.println("Split time for [" + tag + "]: " + (endTime - splitTime) + " ms");
splitTime = endTime;
}
public void end() {
end("");
}
public void end(String tag) {
endTime = System.currentTimeMillis();
System.out.println("Final time for [" + tag + "]: " + (endTime - startTime) + " ms");
}
}
Sample of use:
public static Schedule getSchedule(Activity activity_context) {
String scheduleJson = null;
Schedule schedule = null;
/*->*/ Stopwatch stopwatch = new Stopwatch();
InputStream scheduleJsonInputStream = activity_context.getResources().openRawResource(R.raw.skating_times);
/*->*/ stopwatch.split("open raw resource");
scheduleJson = FileToString.convertStreamToString(scheduleJsonInputStream);
/*->*/ stopwatch.split("file to string");
schedule = new Gson().fromJson(scheduleJson, Schedule.class);
/*->*/ stopwatch.split("parse Json");
/*->*/ stopwatch.end("Method getSchedule");
return schedule;
}
Sample of console output:
Split time for [file to string]: 672 ms
Split time for [parse Json]: 893 ms
Final time for [get Schedule]: 1565 ms

In Java 8 a new class named Instant is introduced. As per doc:
Instant represents the start of a nanosecond on the time line. This
class is useful for generating a time stamp to represent machine time.
The range of an instant requires the storage of a number larger than a
long. To achieve this, the class stores a long representing
epoch-seconds and an int representing nanosecond-of-second, which will
always be between 0 and 999,999,999. The epoch-seconds are measured
from the standard Java epoch of 1970-01-01T00:00:00Z where instants
after the epoch have positive values, and earlier instants have
negative values. For both the epoch-second and nanosecond parts, a
larger value is always later on the time-line than a smaller value.
This can be used as:
Instant start = Instant.now();
try {
Thread.sleep(7000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Instant end = Instant.now();
System.out.println(Duration.between(start, end));
It prints PT7.001S.

You can use stopwatch class from spring core project:
Code:
StopWatch stopWatch = new StopWatch()
stopWatch.start(); //start stopwatch
// write your function or line of code.
stopWatch.stop(); //stop stopwatch
stopWatch.getTotalTimeMillis() ; ///get total time
Documentation for Stopwatch:
Simple stop watch, allowing for timing of a number of tasks, exposing total running time and running time for each named task.
Conceals use of System.currentTimeMillis(), improving the readability of application code and reducing the likelihood of calculation errors.
Note that this object is not designed to be thread-safe and does not use synchronization.
This class is normally used to verify performance during proof-of-concepts and in development, rather than as part of production applications.

Get actual time (java, c) synchronized

i am working on easy game(just for fun).
I have server in c and client in java.
I want get actual time on server and on client, but I can not come to the same results time.
On server i am using:
// the system time
SYSTEMTIME systemTime;
GetSystemTime(&systemTime);
// the current file time
FILETIME fileTime;
SystemTimeToFileTime(&systemTime, &fileTime);
// filetime in 100 nanosecond resolution
ULONGLONG fileTimeNano100;
fileTimeNano100 = (((ULONGLONG) fileTime.dwHighDateTime) << 32) + fileTime.dwLowDateTime;
//to milliseconds and unix windows epoche offset removed
ULONGLONG posixTime = fileTimeNano100 / 10000 - 11644473600000;
return posixTime;
And i am getting time in format(output): 1750721123
On client i am using
long lDateTime = new Date().getTime();
System.out.println("Date() - Time in milliseconds: " + lDateTime);
Calendar lCDateTime = Calendar.getInstance();
System.out.println("Calender - Time in milliseconds :" + lCDateTime.getTimeInMillis());
And i am gettin format(output):
Calender - Time in milliseconds :1419089968022
Date() - Time in milliseconds: 1419089968022
Why? Where is the problem? How can i get the same TIME?
Both programs run on the same pc(win 8.1)

First of all. First block of code doesn't seem to be standard C code at all or rather you use some libraries that I just simply doesn't know.
There is no simple way to get actual time with less than a second accuracy in standard C. But here is the example with Java and C that actually works, so I hope this would help.
Java
package stackOverflow;
import java.util.Date;
public class Main {
public static void main(String[] args) {
long lDateTime = new Date().getTime();
System.out.println(lDateTime/1000);
}
}
Output: 1436200408
C
#include<stdio.h>
#include<stdlib.h>
#include<sys/time.h>
#include<time.h>
int main(void) {
struct timeval tv;
gettimeofday(&tv, NULL);
printf("%ld\n", tv.tv_sec);
return 0;
}
Output: 1436200418

Convert Minutes to milliseconds Java/android

I am trying to convert given number of minutes into milliseconds.
For eg: 15mins or 20mins or 44mins should be converted to milliseconds programmatically.
I tried the below:
Calendar alarmCalendar = Calendar.getInstance();
alarmCalendar.set(Calendar.MINUTE,15);
long alarmTime = alarmCalendar.getTimeInMillis();
Log.e("Milli", "seconds"+alarmTime);
This doesn't give the right value? What is the best way to convert this?

TimeUnit.MINUTES.toMillis(yourMinutes)
see TimeUnit javadoc (android)

int minutes = 42;
long millis = minutes * 60 * 1000;

1 minute = 60000 millisecs.
int minutes = 1;
long milliseconds = minutes * 60000;

In Java 8+, use java.time.
java.time.Duration.ofMinutes(15).toMillis();

This answer is in reference to Android using Kotlin-
So if you are using MaterialTimePicker or TimePicker then you can get the hours and minutes values stored in the picker. Then use TimeUnit.HOURS.toMillis(picker.hour.toLong()) and TimeUnit.MINUTES.toMillis(picker.minutes.toLong()) to convert the received time to milliseconds and then add both the values to get the total time in Milliseconds which you can further use to store in Room Database for entering time and fetching when required.
Code for reference :
binding.timeStart.setOnClickListener {
openTimePicker()
picker.addOnPositiveButtonClickListener {
val h = picker.hour
val m = picker.minute
binding.timeStart.text = "$h:$m"
Timber.d("Start Time - $h: $m")
try {
val hour = TimeUnit.HOURS.toMillis(h.toLong())
val minute = TimeUnit.MINUTES.toMillis(m.toLong())
val totalTime = hour + minute
Timber.d("Hour - $hour, Minute - $minute, Total = $totalTime")
timeStart = totalTime
} catch (e: Exception) {
Timber.d("$e")
}
}
}
private fun openTimePicker() {
picker = MaterialTimePicker.Builder()
.setTimeFormat(TimeFormat.CLOCK_12H)
.setHour(12)
.setMinute(10)
.setTitleText("Set Start Time")
.build()
picker.show(childFragmentManager, "TAG")
}

This gives you the time in milli.
long currentTime = System.currentTimeMillis()
Handler handler = new Handler();
long waitTime = currentTime + (15*60*1000);
handler.postDelayed(new Runnable() {
public void run() {
// Alert or do something here.
}
}, waitTime);
This piece of code sleeps for 15 minutes and then executes the handler's run method. This way you can raise an alarm etc...

How to time Java program execution speed

How do you time the execution of a java program? I'm not sure what class I should use to do this.
I'm kinda looking for something like:
// Some timer starts here
for (int i = 0; i < length; i++) {
// Do something
}
// End timer here
System.out.println("Total execution time: " + totalExecutionTime);

final long startTime = System.currentTimeMillis();
for (int i = 0; i < length; i++) {
// Do something
}
final long endTime = System.currentTimeMillis();
System.out.println("Total execution time: " + (endTime - startTime));

Be aware that there are some issues where System#nanoTime() cannot be reliably used on multi-core CPU's to record elapsed time ... each core has maintains its own TSC (Time Stamp Counter): this counter is used to obtain the nano time (really it is the number of ticks since the CPU booted).
Hence, unless the OS does some TSC time warping to keep the cores in sync, then if a thread gets scheduled on one core when the initial time reading is taken, then switched to a different core, the relative time can sporadically appear to jump backwards and forwards.
I observed this some time ago on AMD/Solaris where elapsed times between two timing points were sometimes coming back as either negative values or unexpectedly large positive numbers. There was a Solaris kernel patch and a BIOS setting required to force the AMD PowerNow! off, which appeared to solved it.
Also, there is (AFAIK) a so-far unfixed bug when using java System#nanoTime() in a VirtualBox environment; causing all sorts of bizarre intermittent threading problems for us as much of the java.util.concurrency package relies on nano time.
See also:
Is System.nanoTime() completely useless?
http://vbox.innotek.de/pipermail/vbox-trac/2010-January/135631.html

You get the current system time, in milliseconds:
final long startTime = System.currentTimeMillis();
Then you do what you're going to do:
for (int i = 0; i < length; i++) {
// Do something
}
Then you see how long it took:
final long elapsedTimeMillis = System.currentTimeMillis() - startTime;

You can make use of System#nanoTime(). Get it before and after the execution and just do the math. It's preferred above System#currentTimeMillis() because it has a better precision. Depending on the hardware and the platform used, you may otherwise get an incorrect gap in elapsed time. Here with Core2Duo on Windows, between about 0 and ~15ms actually nothing can be calculated.
A more advanced tool is a profiler.

Here are a few ways to find the execution time in Java:
1) System.nanoTime()
long startTime = System.nanoTime();
.....your code....
long endTime = System.nanoTime();
long totalTime = endTime - startTime;
System.out.println("Execution time in nanoseconds : " + totalTime);
System.out.println("Execution time in milliseconds : " + totalTime / 1000000);
2) System.currentTimeMillis()
long startTime = System.currentTimeMillis();
.....your code....
long endTime = System.currentTimeMillis();
long totalTime = endTime - startTime;
System.out.println("Execution time in milliseconds : " + totalTime);
3) Instant.now()
long startTime = Instant.now().toEpochMilli();
.....your code....
long endTime = Instant.now().toEpochMilli();
long totalTime = endTime - startTime;
System.out.println("Execution time in milliseconds: " + totalTime);
or
Instant start = Instant.now();
.....your code....
Instant end = Instant.now();
Duration interval = Duration.between(start, end);
System.out.println("Execution time in seconds: " +interval.getSeconds());
4) Date.getTime()
long startTime = new Date().getTime();
.....your code....
long endTime = new Date().getTime();
long totalTime = endTime - startTime;
System.out.println("Execution time in milliseconds: " + totalTime);

For simple stuff, System.currentTimeMillis() can work.
It's actually so common that my IDE is setup so that upon entering "t0" it generates me the following line:
final long t0 = System.currentTimeMillis()
But for more complicated things, you'll probably want to use statistical time measurements, like here (scroll down a bit and look at the time measurements expressed including standard deviations etc.):
http://perf4j.codehaus.org/devguide.html

Using AOP/AspectJ and #Loggable annotation from jcabi-aspects you can do it easy and compact:
#Loggable(Loggable.DEBUG)
public String getSomeResult() {
// return some value
}
Every call to this method will be sent to SLF4J logging facility with DEBUG logging level. And every log message will include execution time.

use long startTime=System.currentTimeMillis() for start time, at the top of the loop
put long endTime= System.currentTimeMillis(); outside the end of the loop. You'll have to subtract the values to get the runtime in milliseconds.
If you want time in nanoseconds, check out System.nanoTime()

I created a higher order function which takes the code you want to measure in/as a lambda:
class Utils {
public static <T> T timeIt(String msg, Supplier<T> s) {
long startTime = System.nanoTime();
T t = s.get();
long endTime = System.nanoTime();
System.out.println(msg + ": " + (endTime - startTime) + " ns");
return t;
}
public static void timeIt(String msg, Runnable r) {
timeIt(msg, () -> {r.run(); return null; });
}
}
Call it like that:
Utils.timeIt("code 0", () ->
System.out.println("Hallo")
);
// in case you need the result of the lambda
int i = Utils.timeIt("code 1", () ->
5 * 5
);
Output:
code 0: 180528 ns
code 1: 12003 ns
Special thanks to Andy Turner who helped me cut down the redundancy. See here.

You can use Stopwatch
import com.google.common.base.Stopwatch;
Stopwatch timer = Stopwatch.createStarted();
//lines to be executed
System.out.println("Execution time= " + timer.stop());

Have a look at System.currentTimeMillis().

You may also try Perf4J. Its a neat way of doing what you are looking for, and helps in aggregated performance statistics like mean, minimum, maximum, standard deviation and transactions per second over a set time span. An extract from http://perf4j.codehaus.org/devguide.html:
StopWatch stopWatch = new LoggingStopWatch();
try {
// the code block being timed - this is just a dummy example
long sleepTime = (long)(Math.random() * 1000L);
Thread.sleep(sleepTime);
if (sleepTime > 500L) {
throw new Exception("Throwing exception");
}
stopWatch.stop("codeBlock2.success", "Sleep time was < 500 ms");
} catch (Exception e) {
stopWatch.stop("codeBlock2.failure", "Exception was: " + e);
}
Output:
INFO: start[1230493236109] time[447] tag[codeBlock2.success] message[Sleep time was < 500 ms]
INFO: start[1230493236719] time[567] tag[codeBlock2.failure] message[Exception was: java.lang.Exception: Throwing exception]
INFO: start[1230493237286] time[986] tag[codeBlock2.failure] message[Exception was: java.lang.Exception: Throwing exception]
INFO: start[1230493238273] time[194] tag[codeBlock2.success] message[Sleep time was < 500 ms]
INFO: start[1230493238467] time[463] tag[codeBlock2.success] message[Sleep time was < 500 ms]
INFO: start[1230493238930] time[310] tag[codeBlock2.success] message[Sleep time was < 500 ms]
INFO: start[1230493239241] time[610] tag[codeBlock2.failure] message[Exception was: java.lang.Exception: Throwing exception]
INFO: start[1230493239852] time[84] tag[codeBlock2.success] message[Sleep time was < 500 ms]
INFO: start[1230493239937] time[30] tag[codeBlock2.success] message[Sleep time was < 500 ms]
INFO: start[1230493239968] time[852] tag[codeBlock2.failure] message[Exception was: java.lang.Exception: Throwing exception]

public class someClass
{
public static void main(String[] args) // your app start point
{
long start = java.util.Calendar.getInstance().getTimeInMillis();
... your stuff ...
long end = java.util.Calendar.getInstance().getTimeInMillis();
System.out.println("it took this long to complete this stuff: " + (end - start) + "ms");
}
}

Using System.currentTimeMillis() is the proper way of doing this. But, if you use command line, and you want to time the whole program approximately and quickly, think about:
time java App
which allows you not to modify the code and time your App.