src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/tools/HeapSummary.java

*** 27,36 ****
--- 27,37 ----
  import java.util.*;
  import sun.jvm.hotspot.gc.g1.*;
  import sun.jvm.hotspot.gc.parallel.*;
  import sun.jvm.hotspot.gc.serial.*;
  import sun.jvm.hotspot.gc.shared.*;
+ import sun.jvm.hotspot.gc.z.*;
  import sun.jvm.hotspot.debugger.JVMDebugger;
  import sun.jvm.hotspot.memory.*;
  import sun.jvm.hotspot.oops.*;
  import sun.jvm.hotspot.runtime.*;
  
*** 122,131 ****
--- 123,135 ----
           System.out.println("PS Old Generation");
           printValMB("capacity = ", oldGen.capacity());
           printValMB("used     = ", oldGen.used());
           printValMB("free     = ", oldFree);
           System.out.println(alignment + (double)oldGen.used() * 100.0 / oldGen.capacity() + "% used");
+       } else if (heap instanceof ZCollectedHeap) {
+          ZCollectedHeap zheap = (ZCollectedHeap) heap;
+          zheap.printOn(System.out);
        } else {
           throw new RuntimeException("unknown CollectedHeap type : " + heap.getClass());
        }
  
        System.out.println();
*** 160,169 ****
--- 164,181 ----
             l = getFlagValue("ParallelGCThreads", flagMap);
             System.out.println("with " + l + " thread(s)");
             return;
         }
  
+        l = getFlagValue("UseZGC", flagMap);
+        if (l == 1L) {
+            System.out.print("ZGC ");
+            l = getFlagValue("ParallelGCThreads", flagMap);
+            System.out.println("with " + l + " thread(s)");
+            return;
+        }
+ 
         System.out.println("Mark Sweep Compact GC");
     }
  
     private void printPSYoungGen(PSYoungGen youngGen) {
        System.out.println("PS Young Generation");