public static double memoryUsed() throws Exception {
        final MemoryUsage heapMemoryUsage = MXBeanHolder.memoryMxBean.getHeapMemoryUsage();
        return (double) (heapMemoryUsage.getUsed()) / heapMemoryUsage.getMax();
    }
Returns the heap memory used for the current java process.
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/util/JvmTools.java