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rangareddy · May 22, 2021 · 482f5ca · 482f5ca
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diff --git a/array_size_exceeds.md b/array_size_exceeds.md
@@ -11,16 +11,16 @@ Requested array size exceeds VM limit indicates that indicates that the applicat
 In most cases the problem is either a configuration issue (heap size too small), or a bug that results in an application attempting to create a huge array, for example, when the number of elements in the array are computed using an algorithm that computes an incorrect size.
 
 ```java
-package com.ranga.oom;
+// ArraySizeExceedsLimitDemo.java
+// JVM Parameters: -Xms10m -Xmx10m
 
-public class ArraySizeExceedsLimit {
+package com.ranga.java.oom;
+
+public class ArraySizeExceedsLimitDemo {
     private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE;
-    public static void main(String[] args) {
-        arraySizeChecker();
-    }
 
-    public static void arraySizeChecker(){
-        int[] bytes=new int[MAX_ARRAY_SIZE];
+    public static void main(String[] args) {
+        int[] bytes = new int[MAX_ARRAY_SIZE];
     }
 }
 ```
@@ -29,8 +29,7 @@ The maximum positive int in Java is 2^31 – 1 = 2,147,483,647. And the platform
 $ javac ArraySizeExceedsLimitDemo.java
 $ java -Xms10m -Xmx10m ArraySizeExceedsLimitDemo
 Exception in thread "main" java.lang.OutOfMemoryError: Requested array size exceeds VM limit
-  at ArraySizeExceedsLimitDemo.arraySizeChecker(ArraySizeExceedsLimitDemo.java:8)
-  at ArraySizeExceedsLimitDemo.main(ArraySizeExceedsLimitDemo.java:4)
+	at com.ranga.java.oom.ArraySizeExceedsLimitDemo.main(ArraySizeExceedsLimitDemo.java:10)
 ```
 
 The java.lang.OutOfMemoryError: Requested array size exceeds VM limit can appear as a result of either of the following situations:

diff --git a/meta_space.md b/meta_space.md
@@ -48,24 +48,58 @@ jstat -gcmetacapacity 11236
 Hence, this type of error is thrown by JVM for having a large number of big classes. The following example uses javassist package from the link: http://jboss-javassist.github.io/javassist/ which enables Java bytecode manipulation.
 
 ```java
-import javassist.CannotCompileException;
+// MetaspaceDemo.java
+// JVM Parameters: -XX:MetaspaceSize=64M -XX:MaxMetaspaceSize=64M
+// javac -cp javassist.jar MetaspaceDemo.java
+// java -cp .:javassist.jar MetaspaceDemo
+
+package com.ranga.java.oom;
+
 import javassist.ClassPool;
 
 public class MetaspaceDemo {
-    public static void main(String args[]) throws Exception
-    {
+    public static void main(String[] args) throws Exception {
         ClassPool classPool = ClassPool.getDefault();
-
-        for (int i = 0; i <100000000 ; i++) {
-            Class claz = classPool.makeClass("MetaspaceDemo" + i).toClass();
+        for (int i = 0; i < 70000; i++) {
+            Class claz = classPool.makeClass("MetaspaceDemo " + i).toClass();
+            System.out.println(claz.getName());
         }
     }
 }
+```
 
-javac -cp javassist.jar MetaspaceDemo.java
-java -cp .:javassist.jar MetaspaceDemo
+```sh
+
+$ javac -cp javassist.jar MetaspaceDemo.java
+$ java -cp .:javassist.jar MetaspaceDemo
+
+MetaspaceDemo 1
+MetaspaceDemo 2
+MetaspaceDemo 3
+..
+..
+MetaspaceDemo 68664
+MetaspaceDemo 68665
+
+Exception in thread "main" javassist.CannotCompileException: by java.lang.OutOfMemoryError: Metaspace
+	at javassist.ClassPool.toClass(ClassPool.java:1085)
+	at javassist.ClassPool.toClass(ClassPool.java:1028)
+	at javassist.ClassPool.toClass(ClassPool.java:986)
+	at javassist.CtClass.toClass(CtClass.java:1079)
+	at com.ranga.java.oom.MetaspaceDemo.main(MetaspaceDemo.java:14)
+Caused by: java.lang.OutOfMemoryError: Metaspace
+	at java.lang.ClassLoader.defineClass1(Native Method)
+	at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
+	at java.lang.ClassLoader.defineClass(ClassLoader.java:642)
+	at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
+	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
+	at java.lang.reflect.Method.invoke(Method.java:498)
+	at javassist.ClassPool.toClass2(ClassPool.java:1098)
+	at javassist.ClassPool.toClass(ClassPool.java:1079)
+	... 4 more
 ```
-This code will keep generating new classes and loading their definitions to Metaspace until the space is fully utilized and the java.lang.OutOfMemoryError: Metaspace is thrown. When launched with -XX:MaxMetaspaceSize=64m then on Mac OS X my Java 1.8.0_05 dies at around 70, 000 classes loaded.
+
+This code will keep generating new classes and loading their definitions to Metaspace until the space is fully utilized and the **java.lang.OutOfMemoryError: Metaspace** is thrown. When launched with **-XX:MaxMetaspaceSize=64m** then on Mac OS X my Java 1.8.0_05 dies at around 70,000 classes loaded.
 
 The above code will continue to generate new classes at runtime and load their definitions into Metaspace until the space is fully utilized and java.lang.OutOfMemoryError: Metaspace is thrown.
 

diff --git a/native_thread.md b/native_thread.md
@@ -71,19 +71,22 @@ public class NativeThreadDemo {
 ```
 
 ```sh
-javac NativeThreadDemo.java
-java NativeThreadDemo
+$ javac NativeThreadDemo.java
+$ java NativeThreadDemo
+
 1
 2
 ...
 
-4069
-4070
+8160
+8161
+8162
+8163
+8164
 Exception in thread "main" java.lang.OutOfMemoryError: unable to create new native thread
-  at java.lang.Thread.start0(Native Method)
-  at java.lang.Thread.start(Thread.java:717)
-  at NativeThreadDemo.runThreads(NativeThreadDemo.java:18)
-  at NativeThreadDemo.main(NativeThreadDemo.java:3)
+	at java.lang.Thread.start0(Native Method)
+	at java.lang.Thread.start(Thread.java:717)
+	at com.ranga.java.oom.NativeThreadDemo.main(NativeThreadDemo.java:16)
 ```
 The native thread limit is platform-dependent so it will take a different number of threads in order to reach to the limit.