在 64 位操作系统上运行的 32 位 JVM 的最大 Java 堆大小是多少？

import java.lang.Runtime;

public class MaxMemory {
    public static void main(String[] args) {
        Runtime rt = Runtime.getRuntime();
        long totalMem = rt.totalMemory();
        long maxMem = rt.maxMemory();
        long freeMem = rt.freeMemory();
        double megs = 1048576.0;

        System.out.println("Total Memory: " + totalMem + " (" + (totalMem/megs) + " MiB)");
        System.out.println("Max Memory:   " + maxMem + " (" + (maxMem/megs) + " MiB)");
        System.out.println("Free Memory:  " + freeMem + " (" + (freeMem/megs) + " MiB)");
    }
}