[Q#2015463][A#2015524] How to view the current heap size that an application is using?

https://stackoverflow.com/q/2015463

I think I increased my heap size to 1 GB in NetBeans since I changed the config to look like this: After I restarted NetBeans, can I be sure that my app is given 1 GB now? Is there a way to verify this?

Answer

https://stackoverflow.com/a/2015524

Use this code: It was useful to me to know it.

APIzation

// 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();

package com.stackoverflow.api;

public class Human2015524 {

  public static MemoryInfo getMemoryInfo() {
    // 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();

    return new MemoryInfo(heapSize, heapMaxSize, heapFreeSize);
  }
}

class MemoryInfo {

  private long heapSize;
  private long heapMaxSize;
  private long heapFreeSize;

  public MemoryInfo(long heapSize, long heapMaxSize, long heapFreeSize) {
    this.heapSize = heapSize;
    this.heapMaxSize = heapMaxSize;
    this.heapFreeSize = heapFreeSize;
  }

  public long getHeapSize() {
    return heapSize;
  }

  public long getHeapMaxSize() {
    return heapMaxSize;
  }

  public long getHeapFreeSize() {
    return heapFreeSize;
  }
}

package com.stackoverflow.api;

/**
 * How to view the current heap size that an application is using?
 *
 * @author APIzator
 * @see <a href="https://stackoverflow.com/a/2015524">https://stackoverflow.com/a/2015524</a>
 */
public class APIzator2015524 {

  public static long viewSize() throws Exception {
    // 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();
    return Runtime.getRuntime().freeMemory();
  }
}