The -mx parameter to the JVM tells it what the maximum size of the heap should be, but the JVM often doesn't allocate all that memory at the start.

参数- mx告诉jvm堆有多大，但JVM通常不在一开始就分配所有这些内存。

youdao

The PENTAX MX-1 features a 4X optical zoom lens offering a large maximum aperture of F1.8 to F2.5 and 28mm wide-angle coverage (in the 35mm format).

ENGADGET: Pentax launches brass-bodied MX-1 point-and-shoot: 12MP with 4X zoom (update: now with hands-on photos)