Question

I met an OutOfMemoryError: Java Heap Space when I tried to attach a large attachment. When emails with some large files (say 50M) are sent, the error will be thrown.

The code is like this:

//add attaches
if (vo.getAttaches() != null) {
    InputStream iStream = null;
    ByteArrayDataSource bdSource = null;
    String filename = null;

    for (int i = 0; i < vo.getAttaches().length; i++) {
         iStream = new FileInputStream(vo.getAttaches()[i]);
         bdSource = new ByteArrayDataSource(iStream, null);
         filename = vo.getAttachesFileName()[i];
         email.attach(bdSource, MimeUtility.encodeText(filename), filename);
    }
}

It is bdSource = new ByteArrayDataSource(iStream, null) throws the exception above. I had read “out of memory using java mail” but i don’t understand. How can I upload large attaches? If I define a buffer like byte[1024], then how to code email.attach()? Should all data in buffer use the same filename?

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Update: Thanks for your kindness. I use FileDataSource instead of ByteArrayDataSource, it seems that there’s no exception in my send() function. But I still can not send emails with large attach. The apache james got this error:

    java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:2786)
    at java.io.ByteArrayOutputStream.toByteArray(ByteArrayOutputStream.java:133)
    at com.sun.mail.util.ASCIIUtility.getBytes(ASCIIUtility.java:261)
    at javax.mail.internet.MimeMessage.parse(MimeMessage.java:338)
    at org.apache.james.core.MimeMessageWrapper.parse(MimeMessageWrapper.java:477)
    at org.apache.james.core.MimeMessageWrapper.loadMessage(MimeMessageWrapper.java:205)
    at org.apache.james.core.MimeMessageWrapper.checkModifyHeaders(MimeMessageWrapper.java:414)
    at org.apache.james.core.MimeMessageWrapper.setHeader(MimeMessageWrapper.java:426)
    at org.apache.james.core.MimeMessageCopyOnWriteProxy.setHeader(MimeMessageCopyOnWriteProxy.java:652)
    at org.apache.james.transport.mailets.UsersRepositoryAliasingForwarding.service(UsersRepositoryAliasingForwarding.java:101)
    at org.apache.james.transport.mailets.LocalDelivery.service(LocalDelivery.java:64)
    at org.apache.james.transport.LinearProcessor.service(LinearProcessor.java:424)
    at org.apache.james.transport.JamesSpoolManager.process(JamesSpoolManager.java:405)
    at org.apache.james.transport.JamesSpoolManager.run(JamesSpoolManager.java:309)
    at java.lang.Thread.run(Thread.java:619)
03/07/12 13:08:33 ERROR spoolmanager: An error occurred processing Mail1341292071375-0 through transport
03/07/12 13:08:33 ERROR spoolmanager: Result was error
03/07/12 13:08:33 ERROR spoolmanager: Exception in processor <error>
java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:2786)
    at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:94)
    at org.apache.james.core.MimeMessageUtil.copyStream(MimeMessageUtil.java:168)
    at org.apache.james.core.MimeMessageWrapper.writeTo(MimeMessageWrapper.java:276)
    at org.apache.james.core.MimeMessageUtil.writeTo(MimeMessageUtil.java:66)
    at org.apache.james.core.MimeMessageUtil.writeTo(MimeMessageUtil.java:50)
    at org.apache.james.mailrepository.MessageInputStream.writeStream(MessageInputStream.java:131)
    at org.apache.james.mailrepository.MessageInputStream.<init>(MessageInputStream.java:101)
    at org.apache.james.mailrepository.JDBCMailRepository.store(JDBCMailRepository.java:718)
    at org.apache.james.transport.mailets.ToRepository.service(ToRepository.java:98)
    at org.apache.james.transport.LinearProcessor.service(LinearProcessor.java:424)
    at org.apache.james.transport.JamesSpoolManager.process(JamesSpoolManager.java:405)
    at org.apache.james.transport.JamesSpoolManager.run(JamesSpoolManager.java:309)
    at java.lang.Thread.run(Thread.java:619)
03/07/12 13:08:33 ERROR spoolmanager: An error occurred processing Mail1341292071375-0 through error
03/07/12 13:08:33 ERROR spoolmanager: Result was ghost

Answer 1

The problem is that you’re trying to store the whole file in memory while composing the message, which actually isn’t usually necessary. If you’re attaching real files, then you are far better off using a javax.activation.FileDataSource instead of a javax.mail.util.ByteArrayDataSource (both implement the DataSource interface) as that can allow the data to be streamed rather than being held in memory.