java heap memory usage exception when using FOR lOOP

Question

When i run the below program i got the exception when for loop begins its execution at i=1031521. How to over come memory usage of this type?

class wwww
    {
        public static void main(String args[])
        {
            String abc[]=new String[4194304];
            String wwf="";
            int s_count=524286;
            for(int i=0;i<4194304;i++)
            {
                System.out.println("----------enter--------"+i);
                abc[i]=""+i;
                System.out.println("----------exit--------"+i);
            }
        }
    }

The exception is:

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:2882)
    at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.
java:100)
    at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:390
)
    at java.lang.StringBuilder.append(StringBuilder.java:119)
    at wwww.main(wwww.java:12)

you can find your answer here. stackoverflow.com/questions/4308364/… — Ali Imran
– Ali Imran, Commented Nov 28, 2012 at 6:46

Abubakkar · Accepted Answer · 2012-11-28 06:50:47Z

1

This is because your your uses up all the heap space allocated to your jvm.

You can use argument while running the program to specify the heap size that you would like to allocate.

This is an example:

java -Xmx256m MyClass

Here a maximum of 256 MB of heap space will be allocated

answered Nov 28, 2012 at 6:50

Abubakkar

15.7k8 gold badges58 silver badges84 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

user207421 · Accepted Answer · 2012-11-28 07:45:57Z

1

How to over come memory usage of this type?

Don't perform memory usage of this type. You are creating 4194304 strings, of the general form ""+i. You don't need 4194304 strings of that form all at once. You only need one of them at a time, if any, and you can create it every time you need it.

answered Nov 28, 2012 at 7:45

user207421

312k45 gold badges324 silver badges493 bronze badges

Comments

NPE · Accepted Answer · 2012-11-28 06:52:28Z

0

You could either:

Increase the heap size that you give to your program. This is done via the -Xmx command-line argument to java.
Re-engineer the program to use less memory. Do you really need to keep all those strings in memory at once?

answered Nov 28, 2012 at 6:52

NPE

503k114 gold badges970 silver badges1k bronze badges

Collectives™ on Stack Overflow

java heap memory usage exception when using FOR lOOP

3 Answers 3

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related