Syntax
-XmxSIZE
        
            With this option you can change the maximum heap size the Java
            virtual machine can address on Java 1.4 systems. By default this
            is 64 MB. For large files this might not be enough. Use
            this option to encrease the heap size,
            e.g. -Xmx512m, which would encrase the heap size
            to 512 MB. On older Java systems the syntax of this option is
            different (see java --help).