The Java™ heap size determines how much memory should be reserved for the JVM process. By default, Webform Server sets both the initial and the maximum Java heap size (-Xms and -Xmx settings) to 50 MB, although the default -Xms and -Xmx values are blank. This should be sufficient for most Webform Server deployments.
However, if your solution requires more memory to be allocated to the Java heap, you can modify these settings through the WebSphere® Application Server Administration Console. You should change both the -Xmx and -Xms settings to the same value to prevent the JVM from dynamically allocating and de-allocating memory at run time.