blocks|key|1127809|text|jstat就是你要找的东西。它将打印每秒的统计数据(或您指定的任何数据)，然后您可以分析输出以找到最大值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1127810|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/6/docs/technotes/tools/share/jstat.html^0|0|5|0|5|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

<a href="http://docs.oracle.com/javase/6/docs/technotes/tools/share/jstat.html" rel="nofollow"><code>jstat</code></a> is what you are after. It will print stats every second (or whatever you specify) then you can analyse the output to find the maximum.

blocks|key|1125219|text|您可以在应用程序中执行此操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125220|ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();|code-block|syntax|javascript|1125221|然后对返回的MemoryUsage对象使用getCommitted()、getUsed()和getMax()方法。|offset|length|style|CODE|1125222|entityMap^0|0|0|6|B|L|E|10|9|1A|8|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|N|$]]

You could do it from within the application:

<pre><code>ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
</code></pre>

Then use the <code>getCommitted()</code>, <code>getUsed()</code> and <code>getMax()</code> methods on the returned <code>MemoryUsage</code> object.

blocks|key|1127814|text|您需要使用以下内容来分析应用程序：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1127815|http://java.sun.com/developer/technicalArticles/J2SE/jconsole.html#LowMemoryDetection|offset|length|1127816|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|2D|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@$D|O|E|P|1|Q]]|A|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|C]]]]

You need to profile your application with something like:

<a href="http://java.sun.com/developer/technicalArticles/J2SE/jconsole.html#LowMemoryDetection" rel="nofollow">http://java.sun.com/developer/technicalArticles/J2SE/jconsole.html#LowMemoryDetection</a>

blocks|key|5407314|text|您可以使用下面的方法来获取堆大小的值|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5407315|Runtime.getRuntime().totalMemory()；|5407316|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

U can make use of this below method to get the value of heap size 

Runtime.getRuntime().totalMemory();

blocks|key|5407375|text|可以通过java.lang.Runtime.getRuntime();在程序中获取程序的总已用/空闲内存|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5407376|运行时有几个与内存相关的方法。下面的编码示例演示了它的用法。|5407377|5407378|import+java.util.ArrayList;
import+java.util.List;

public+class+PerformanceTest+{
++private+static+final+long+MEGABYTE+=+1024L+*+1024L;

++public+static+long+bytesToMegabytes(long+bytes)+{
++++return+bytes+/+MEGABYTE;
++}

++public+static+void+main(String[]+args)+{
++++//+I+assume+you+will+know+how+to+create+a+object+Person+yourself...
++++List<Person>+list+=+new+ArrayList<Person>();
++++for+(int+i+=+0;+i+<=+100000;+i%2B%2B)+{
++++++list.add(new+Person("Jim",+"Knopf"));
++++}
++++//+Get+the+Java+runtime
++++Runtime+runtime+=+Runtime.getRuntime();
++++//+Run+the+garbage+collector
++++runtime.gc();
++++//+Calculate+the+used+memory
++++long+memory+=+runtime.totalMemory()+-+runtime.freeMemory();
++++System.out.println("Used+memory+is+bytes:+"+%2B+memory);
++++System.out.println("Used+memory+is+megabytes:+"
++++++++%2B+bytesToMegabytes(memory));
++}
}+|code-block|syntax|javascript|5407379|entityMap^0|4|V|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@]|E|$]]|$1|H|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|I|3|J|5|K|7|U|8|@]|D|@]|E|$L|M]]|$1|N|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|O|$]]

The total used / free memory of an program can be obtained in the program via <code>java.lang.Runtime.getRuntime();</code>

The runtime has several method which relates to the memory. The following coding example demonstrate its usage.

The runtime has several method which relates to the memory. The following coding example demonstrate its usage.

<pre><code>import java.util.ArrayList;
import java.util.List;

public class PerformanceTest {
 private static final long MEGABYTE = 1024L * 1024L;

 public static long bytesToMegabytes(long bytes) {
 return bytes / MEGABYTE;
 }

 public static void main(String[] args) {
 // I assume you will know how to create a object Person yourself...
 List&lt;Person&gt; list = new ArrayList&lt;Person&gt;();
 for (int i = 0; i &lt;= 100000; i++) {
 list.add(new Person("Jim", "Knopf"));
 }
 // Get the Java runtime
 Runtime runtime = Runtime.getRuntime();
 // Run the garbage collector
 runtime.gc();
 // Calculate the used memory
 long memory = runtime.totalMemory() - runtime.freeMemory();
 System.out.println("Used memory is bytes: " + memory);
 System.out.println("Used memory is megabytes: "
 + bytesToMegabytes(memory));
 }
} 
</code></pre>

I am running a big Java application on a cluster and I have much memory available. Thus I plan to start my JVM with a huge maximal heap size and see that it works. However I need to run this multiple times and I want to know how big the heap actually became during the run. I know I could do this with a tool like VisualVM but what if I don't want to run a big ui based application? Is there some paramater I can send to the jvm to get some this sort of memory statistics after my application has terminated? Or perhaps a command line based application that can easily do it?

How can I find max size of Javas heap after run?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在集群上运行一个大型Java应用程序，并且我有很多可用的内存。因此，我计划用一个巨大的最大堆大小启动我的JVM，并查看它是否工作。但是，我需要多次运行它，并且我想知道在运行期间堆实际变得有多大。我知道我可以使用像VisualVM这样的工具来做到这一点，但是如果我不想运行一个基于ui的大型应用程序呢？在我的应用程序终止后，有没有一些参数我可以发送给jvm来获取这种内存统计信息？或者是一个基于命令

问如何在运行后找到Javas堆的最大大小？
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