C:\Users\jjs>jmap -heap 5932
Attaching to process ID 5932, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.91-b15
using thread-local object allocation.
Parallel GC with 4 thread(s)
Heap Configuration:
   MinHeapFreeRatio         = 0
   MaxHeapFreeRatio         = 100
   MaxHeapSize              = 1073741824 (1024.0MB)
   NewSize                  = 42991616 (41.0MB)
   MaxNewSize               = 357564416 (341.0MB)
   OldSize                  = 87031808 (83.0MB)
   NewRatio                 = 2
   SurvivorRatio            = 8
   MetaspaceSize            = 21807104 (20.796875MB)
   CompressedClassSpaceSize = 1073741824 (1024.0MB)
   MaxMetaspaceSize         = 17592186044415 MB
   G1HeapRegionSize         = 0 (0.0MB)
Heap Usage:
PS Young Generation
Eden Space:
   capacity = 60293120 (57.5MB)
   used     = 44166744 (42.120689392089844MB)
   free     = 16126376 (15.379310607910156MB)
   73.25337285580842% used
From Space:
   capacity = 5242880 (5.0MB)
   used     = 0 (0.0MB)
   free     = 5242880 (5.0MB)
   0.0% used
To Space:
   capacity = 14680064 (14.0MB)
   used     = 0 (0.0MB)
   free     = 14680064 (14.0MB)
   0.0% used
PS Old Generation
   capacity = 120061952 (114.5MB)
   used     = 19805592 (18.888084411621094MB)
   free     = 100256360 (95.6119155883789MB)
   16.496143590935453% used
20342 interned Strings occupying 1863208 bytes.

public class JconsoleTest {
    public byte[] b1 = new byte[128 * 1024];
    public static void main(String[] args) {
        try {
            Thread.sleep(5000);
        }catch (InterruptedException e){
            e.printStackTrace();
        }
        System.out.println("start ..");
        fill(1000);
    }
    private static void fill(int n) {
        ArrayList<JconsoleTest> jlist = new ArrayList<>();
        for (int i=0;i<n;i++){
            try {
                Thread.sleep(100);
            }catch (InterruptedException e){
                e.printStackTrace();
            }
            jlist.add(new JconsoleTest());
        }
    }
}

public class Main {
    public static void main(String[] args) {
        //创建一个输入流，让程序卡在这里
        Scanner sc = new Scanner(System.in);
        sc.next();
        new Thread(new Runnable() {
            @Override
            public void run() {
                while(true){
                }
            }
        },"while true线程").start();
        sc.next();
        testWait(new Object());
    }
    private static void testWait(Object obj) {
        System.out.println("----testWait-------");
       new Thread(new Runnable() {
           @Override
           public void run() {
               synchronized (obj){
                   try {
                       obj.wait();
                   }catch (InterruptedException e){
                       e.printStackTrace();
                   }
               }
           }
       },"testWait 线程").start();
    }
}

public class DeadLock implements Runnable {
    private Object obj1;
    private Object obj2;
    public DeadLock(Object obj1, Object obj2) {
        this.obj1 = obj1;
        this.obj2 = obj2;
    }
    @Override
    public void run() {
        synchronized (obj1){
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            synchronized (obj2){
                System.out.println("Hello");
            }
        }
    }
}

public class Main {
    public static void main(String[] args) {
        Object obj1 = new Object();
        Object obj2 = new Object();
        new Thread(new DeadLock(obj1, obj2)).start();
        new Thread(new DeadLock(obj2, obj1)).start();
    }
}