Java array memory allocation

[Martin Lira]

Guys,

What will happen when you do

  
int SIZE = 200 * 1024 *1024; //200MB
byte[] bbuf = new byte [SIZE];

Or in other words can we allocate such large arrays.

Thanks,
Martin

[Ernest Friedman-Hill]

If there's enough memory available, yes. You may have to use Sun's -Xmx switch (or another vendor-specific mechanism) to set the max size of the Java heap.

[Maulin Vasavada]

Hi,

The last I remember I had a question along similar lines and Jim Yingst pointed that as array object have length field which is of type 'int' we can only create arrays of len Integer.MAX_VALUE. Again this is true only if we have sufficient memory to create Integer.MAX_VALUE size array.

I ran the following,

public static void test3() {
byte[] b = new byte[Integer.MAX_VALUE];
}
public static void main(String[] args) {
test3();
}

and got,
java.lang.OutOfMemoryError
Exception in thread "main"

Regards
Maulin
[ March 04, 2005: Message edited by: Maulin Vasavada ]

[David Harkness]

Originally posted by Maulin Vasavada:
byte[] b = new byte[Integer.MAX_VALUE];

Yes well, not everyone has 2GB of RAM devoted exclusively to the JVM!