Adding heap dump capability

src/main/java/de/steamwar/Agent.java

@@ -1,6 +1,12 @@
 package de.steamwar;
 
+import com.ibm.jvm.Dump;
+import com.ibm.jvm.InvalidDumpOptionException;
+
+import java.io.File;
 import java.lang.instrument.Instrumentation;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 public class Agent {
     private Agent() {}
@@ -24,6 +30,13 @@ public class Agent {
                     sampler.stop();
                 sampler = null;
                 break;
+            case "heap":
+                try {
+                    Dump.heapDumpToFile(new File(Main.jarPath.getParentFile(), "heap.phd").getPath());
+                } catch (InvalidDumpOptionException e) {
+                    Logger.getGlobal().log(Level.WARNING, "Could not perform heap dump", e);
+                }
+                break;
         }
     }
 }

src/main/java/de/steamwar/Main.java

@@ -28,10 +28,13 @@ public class Main {
                     System.out.println(vmd.id() + " " + vmd.displayName());
                 }
             }
-        }else if(args.length == 1) {
-            try {
-                VirtualMachine vm = VirtualMachine.attach(args[0]);
+            return;
+        }
 
+        try {
+            VirtualMachine vm = VirtualMachine.attach(args[0]);
+
+            if(args.length == 1 || !"heap".equals(args[1])) {
                 vm.loadAgent(jarPath.getAbsolutePath(), "start");
 
                 System.out.println("Press keyboard to stop sampling...");
@@ -39,13 +42,15 @@ public class Main {
 
                 vm.loadAgent(jarPath.getAbsolutePath(), "stop");
 
-                vm.detach();
-
                 new ProcessBuilder("xdot", "samples.dot").directory(jarPath.getParentFile()).start();
-            } catch (AttachNotSupportedException | IOException | AgentLoadException | AgentInitializationException e) {
-                e.printStackTrace();
+            } else {
+                vm.loadAgent(jarPath.getAbsolutePath(), "heap");
             }
 
+            vm.detach();
+
+        } catch (AttachNotSupportedException | IOException | AgentLoadException | AgentInitializationException e) {
+            e.printStackTrace();
         }
     }
 }