java - 从代码中找出 NewSize 是什么

Question

是否可以像查找堆大小一样显示 java NewSize 参数？

我知道堆大小可以通过使用找到:

Runtime.getRuntime().maxMemory();

NewSize 有类似的东西吗？

Answer 1

您希望MemoryPoolMXBean获取Eden Space和Survivor Space的数值:

for(java.lang.management.MemoryPoolMXBean memoryPoolMXBean :java.lang.management.ManagementFactory.getMemoryPoolMXBeans())
{
    System.out.println("");
    try
    {
        System.out.println("PoolName\t" + memoryPoolMXBean.getName());
        System.out.println("Commited\t" + memoryPoolMXBean.getCollectionUsage().getCommitted());
        System.out.println("Init\t" + memoryPoolMXBean.getCollectionUsage().getInit());
        System.out.println("Max\t" + memoryPoolMXBean.getCollectionUsage().getMax());
        System.out.println("Used\t" + memoryPoolMXBean.getCollectionUsage().getUsed());
    }
    catch (NullPointerException npex)
    {
        npex.printStackTrace();
    }
}

输出:

PoolName    Code Cache
java.lang.NullPointerException
    at com.github.lyubent.example.App.main(App.java:40)

PoolName    Par Eden Space
Commited    0
Init    335544320
Max 335544320
Used    0

PoolName    Par Survivor Space
Commited    0
Init    41943040
Max 41943040
Used    0

PoolName    CMS Old Gen
Commited    0
Init    1728053248
Max 1728053248
Used    0

PoolName    CMS Perm Gen
Commited    0
Init    21757952
Max 85983232
Used    0