58     SecurityManager sm = System.getSecurityManager();
  59     if (sm != null) {
  60       sm.checkPermission(new WhiteBoxPermission("getInstance"));
  61     }
  62     return instance;
  63   }
  64 
  65   static {
  66     registerNatives();
  67   }
  68 
  69   // Get the maximum heap size supporting COOPs
  70   public native long getCompressedOopsMaxHeapSize();
  71   // Arguments
  72   public native void printHeapSizes();
  73 
  74   // Memory
  75   public native long getObjectAddress(Object o);
  76   public native int  getHeapOopSize();
  77   public native int  getVMPageSize();

  78   public native boolean isObjectInOldGen(Object o);
  79   public native long getObjectSize(Object o);
  80 
  81   // Runtime
  82   // Make sure class name is in the correct format
  83   public boolean isClassAlive(String name) {
  84     return isClassAlive0(name.replace('.', '/'));
  85   }
  86   private native boolean isClassAlive0(String name);
  87   public native boolean isMonitorInflated(Object obj);
  88   public native void forceSafepoint();
  89 
  90   // JVMTI
  91   public native void addToBootstrapClassLoaderSearch(String segment);
  92   public native void addToSystemClassLoaderSearch(String segment);
  93 
  94   // G1
  95   public native boolean g1InConcurrentMark();
  96   public native boolean g1IsHumongous(Object o);
  97   public native long    g1NumFreeRegions();

  58     SecurityManager sm = System.getSecurityManager();
  59     if (sm != null) {
  60       sm.checkPermission(new WhiteBoxPermission("getInstance"));
  61     }
  62     return instance;
  63   }
  64 
  65   static {
  66     registerNatives();
  67   }
  68 
  69   // Get the maximum heap size supporting COOPs
  70   public native long getCompressedOopsMaxHeapSize();
  71   // Arguments
  72   public native void printHeapSizes();
  73 
  74   // Memory
  75   public native long getObjectAddress(Object o);
  76   public native int  getHeapOopSize();
  77   public native int  getVMPageSize();
  78   public native long getVMLargePageSize();
  79   public native boolean isObjectInOldGen(Object o);
  80   public native long getObjectSize(Object o);
  81 
  82   // Runtime
  83   // Make sure class name is in the correct format
  84   public boolean isClassAlive(String name) {
  85     return isClassAlive0(name.replace('.', '/'));
  86   }
  87   private native boolean isClassAlive0(String name);
  88   public native boolean isMonitorInflated(Object obj);
  89   public native void forceSafepoint();
  90 
  91   // JVMTI
  92   public native void addToBootstrapClassLoaderSearch(String segment);
  93   public native void addToSystemClassLoaderSearch(String segment);
  94 
  95   // G1
  96   public native boolean g1InConcurrentMark();
  97   public native boolean g1IsHumongous(Object o);
  98   public native long    g1NumFreeRegions();