Increase the memory heap of the Ant build process
To prevent the build process from running out of memory, you can increase the amount of memory allocated to the process. By default, the memory heap is 128 MB, but for large projects you may need more.
In the Maximum heap size field, type the required amount of memory.
The memory heap of the build process is independent of the IntelliJ IDEA memory heap, and is released after the build process is complete. For information about the memory heap allocated by the JVM for running IntelliJ IDEA, see Increase the memory heap of the IDE.