Java 使用更大的堆空间重新启动JVM
我希望能够执行.Jar文件，如果堆空间设置得不够大，它应该使用相同的.Jar文件启动一个新的JVM，但是使用更大的堆空间进行设置，然后关闭第一个JVM和.Jar 我尝试过使用ProcessBuilder，但无法使其工作 它必须跨平台工作Java 使用更大的堆空间重新启动JVM,java,jvm,heap,reboot,relaunch,Java,Jvm,Heap,Reboot,Relaunch,我希望能够执行.Jar文件，如果堆空间设置得不够大，它应该使用相同的.Jar文件启动一个新的JVM，但是使用更大的堆空间进行设置，然后关闭第一个JVM和.Jar 我尝试过使用ProcessBuilder，但无法使其工作 它必须跨平台工作 -ONi我会在外部脚本文件中执行此类工作-使用伪代码： $heap := 128 $ok := true do { exitCode = java -Xmx$heapM -jar myApp.jar if (exitCode = OOME) {
-ONi我会在外部脚本文件中执行此类工作-使用伪代码：
$heap := 128
$ok := true
do {
exitCode = java -Xmx$heapM -jar myApp.jar
if (exitCode = OOME) {
heap += 128
$ok := false
}
while(!$ok)
注意：这只是对这个问题的回答-通常会分配大量内存和/或防止内存泄漏-但我不知道实际的要求/限制您可以使用初始堆大小启动java，还可以指定仅在需要时使用的最大堆大小。我不知道你想做什么，但它可能会模仿你想要的行为
java -Xms256m -Xmx1g -jar myapp.jar
在本例中，您从256M开始，如果应用程序需要更多内存，它将以增量方式占用它，直到1G。我找到了解决方案，它可以跨平台工作。要从代码中重新启动JVM，请使用以下命令。这个答案取自我在这里搜索数小时后发现的另一个问题。如果需要，可以在调用此方法后使用System.exit（0）终止启动新进程的JVM
public static void startSecondJVM() throws Exception {
String separator = System.getProperty("file.separator");
String classpath = System.getProperty("java.class.path");
String path = System.getProperty("java.home")
+ separator + "bin" + separator + "java";
ProcessBuilder processBuilder =
new ProcessBuilder(path, "-Xmx1024m", "-cp",
classpath,
Main.class.getName());
Process process = processBuilder.start();
}
你可以尝试结合这两个来源 MemoryRecoveryTest.java 尝试从
OutOfMemoryError/*License - LGPL
<h3>Recovery from an OutOfMemory Error</h3>
<p>The JavaDocs for Error state, in the first sentence..
<blockquote>"An Error is a subclass of Throwable that indicates
serious problems that a reasonable application should
not try to catch."</blockquote>
<p>This advice has led to the fallacy that an OutOfMemoryError
should not be caught and dealt with.But this demo. shows
that it is quite easy to recover to the point of providing
the user with meaningful information, and advice on how to
proceed.
<p>I aim to make my applications 'unreasonable'.;-)
*/
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JProgressBar;
import javax.swing.JOptionPane;
import javax.swing.JDialog;
import javax.swing.Timer;
import javax.swing.border.EmptyBorder;
import java.util.ArrayList;
/** A demo. showing recovery from an OutOfMemoryError.
Our options once an OOME is encountered are relatively
few, but we can still warn the end user and provide
advice on how to correct the problem.
@author Andrew Thompson */
public class MemoryRecoveryTest {
public static void main(String[] args) {
// reserve a buffer of memory
byte[] buffer = new byte[2^10];
ArrayList<Object> list = new ArrayList<Object>();
final JProgressBar memory = new JProgressBar(
0,
(int)Runtime.getRuntime().totalMemory());
ActionListener listener = new ActionListener() {
@Override
public void actionPerformed(ActionEvent ae) {
memory.setValue(
(int)Runtime.getRuntime().freeMemory() );
}
};
Timer timer = new Timer(500, listener);
timer.start();
JDialog dialog = new JDialog();
dialog.setTitle("Available Memory");
JPanel memoryPanel = new JPanel();
memoryPanel.add(memory);
memoryPanel.setBorder(new EmptyBorder(25,25,25,25));
dialog.add( memoryPanel );
dialog.pack();
dialog.setLocationRelativeTo(null);
dialog.setVisible(true);
dialog.addWindowListener( new WindowAdapter(){
@Override
public void windowClosing(WindowEvent we) {
System.exit(0);
}
} );
// prepare a memory warning panel in advance
JPanel memoryWarning = new JPanel();
memoryWarning.add( new JLabel(
"<HTML><BODY>There is not enough memory to" +
" complete the task!<BR> Use a variant " +
" of the application that assigns more memory.") );
try {
// do our 'memory intensive' task
while(true) {
list.add( new Object() );
}
} catch(OutOfMemoryError oome) {
// provide the VM with some memory 'breathing space'
// by clearing the buffer
buffer = null;
// tell the user what went wrong, and how to fix it
JOptionPane.showMessageDialog(
dialog,
memoryWarning,
"Out of Memory!",
JOptionPane.ERROR_MESSAGE);
}
}
}
为什么要启动一个新的JVM，而不是简单地使用足够高的最大堆大小和永久大小？可以推测，一旦内存耗尽，您只需要使用更大的堆大小。一旦内存耗尽，就无法启动另一个进程。我发现，在不同平台上为不同JVM分配的默认内存是不同的。因此，我需要能够设置它的飞行。此外，我想要一个简单的体验，您只需双击Jar，它就可以处理其余的事情。如果没有涉及终端，用户就不能设置任何标志。你是说，
-Xms=256m-Xmx=1g-ms=256m-mx=1gimport java.awt.EventQueue;
import javax.swing.JOptionPane;
import java.io.File;
class IWantToBeBig {
public static void main(String[] args) throws Exception {
if (args.length==0) {
ProcessBuilder pb = new ProcessBuilder(
"java",
"-jar",
"-Xmx512m",
"big.jar",
"anArgument"
);
pb.directory(new File("."));
Process process = pb.start();
process.waitFor();
System.out.println("Exit value: " + process.exitValue());
} else {
Runnable r = new Runnable() {
public void run() {
JOptionPane.showMessageDialog(
null,
"Max Memory: " +
Runtime.getRuntime().maxMemory() +
" bytes.");
}
};
EventQueue.invokeLater(r);
}
}
}