java - 如何查看应用程序正在使用的当前堆大小？

Question

我认为我在 NetBeans 中将堆大小增加到 1 GB，因为我将配置更改为如下所示:

netbeans_default_options="-J-Xmx1g ......

重新启动 NetBeans 后，我可以确定我的应用程序现在有 1 GB 吗？

有没有办法验证这一点？

Answer 1

使用此代码:

// Get current size of heap in bytes
long heapSize = Runtime.getRuntime().totalMemory(); 

// Get maximum size of heap in bytes. The heap cannot grow beyond this size.// Any attempt will result in an OutOfMemoryException.
long heapMaxSize = Runtime.getRuntime().maxMemory();

 // Get amount of free memory within the heap in bytes. This size will increase // after garbage collection and decrease as new objects are created.
long heapFreeSize = Runtime.getRuntime().freeMemory(); 

知道它对我很有用。