diff --git a/src/main/java/jvm/oom/HeapOOM.java b/src/main/java/jvm/oom/HeapOOM.java
new file mode 100644
index 0000000..116d15e
--- /dev/null
+++ b/src/main/java/jvm/oom/HeapOOM.java
@@ -0,0 +1,21 @@
+package jvm.oom;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * VM args: -Xmx20m -Xms20M -XX:+HeapDumpOnOutOfMemoryError
+ */
+public class HeapOOM {
+
+    static class OOMObject {
+    }
+
+    public static void main(String[] args) throws InterruptedException {
+        List<OOMObject> list = new ArrayList<>();
+
+        while (true) {
+            list.add(new OOMObject());
+        }
+    }
+}
diff --git a/src/main/java/jvm/oom/JavaVMStackSOF.java b/src/main/java/jvm/oom/JavaVMStackSOF.java
new file mode 100644
index 0000000..84230ce
--- /dev/null
+++ b/src/main/java/jvm/oom/JavaVMStackSOF.java
@@ -0,0 +1,24 @@
+package jvm.oom;
+
+/**
+ * VM Args: -Xss228k
+ */
+public class JavaVMStackSOF {
+
+    private int stackLength = 1;
+
+    public void stackLeak() {
+        stackLength++;
+        stackLeak();
+    }
+
+    public static void main(String[] args) {
+        JavaVMStackSOF sof = new JavaVMStackSOF();
+        try {
+            sof.stackLeak();
+        } catch (Throwable e) {
+            System.out.println("stack length: " + sof.stackLength);
+            throw e;
+        }
+    }
+}
diff --git a/src/main/java/threaddemo/DeadlockDemo.java b/src/main/java/threaddemo/DeadlockDemo.java
new file mode 100644
index 0000000..0adeacc
--- /dev/null
+++ b/src/main/java/threaddemo/DeadlockDemo.java
@@ -0,0 +1,39 @@
+package threaddemo;
+
+public class DeadlockDemo {
+    private static final Object resource1 = new Object();
+    private static final Object resource2 = new Object();
+
+    public static void main(String[] args) {
+        new Thread(() -> {
+            synchronized (resource1) {
+                System.out.println(STR."\{Thread.currentThread()}get resource1");
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+                System.out.println(STR."\{Thread.currentThread()} waiting get resource2");
+                synchronized (resource2) {
+                    System.out.println(STR."\{Thread.currentThread()} get resource2");
+                }
+            }
+        },"t1").start();
+
+        new Thread(() -> {
+            synchronized (resource2) {
+                System.out.println(Thread.currentThread() + "get resource2");
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+
+                System.out.println(Thread.currentThread() + "waiting get resource1");
+                synchronized (resource1) {
+                    System.out.println(Thread.currentThread() + "get resource1");
+                }
+            }
+        },"t2").start();
+    }
+}