/*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);
}
}
}
IWantToBeBig.java
确保Process是以指定的内存大小启动的。
import 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);
}
}
}
4条答案
按热度按时间cetgtptt1#
我已经找到了解决方案，它可以跨平台工作。要从代码中重新启动JVM，请使用以下代码。这个答案来自我在这里搜索了几个小时后发现的另一个问题。如果需要，可以在它后面使用System.exit（0），在调用此方法后终止启动新进程的JVM。
nnt7mjpx2#
你可以用一个初始的堆大小启动java，也可以指定一个最大的堆大小，它只会在需要的时候使用。我不知道你想做什么，但它可能会模拟你想要的行为？
在本例中，您从256M开始，如果应用需要更多内存，它将逐渐增加，直到1G。
umuewwlo3#
您可以尝试将这两个来源结合起来。
MemoryRecoveryTest.java
尝试从
OutOfMemoryError恢复。IWantToBeBig.java
确保
Process是以指定的内存大小启动的。ulydmbyx4#
我会在一个外部脚本文件中进行这种工作--在伪代码中：
捕获OOME并使用自定义代码退出应该总是可能的。这种方法有一个问题-如果$heap值超过了目标系统可能的最大堆空间（例如：在Win32系统上约为1.4 GB），则不会终止。
注意：这只是问题的一个答案--通常会分配大量的内存和/或防止内存泄漏--但我不知道实际的要求/限制