Update README.md

Author: engineerscodes

README.md

@@ -14,3 +14,4 @@ My Daily Java Works
 # THREAD NOTES
  1) [Potential concurrency issue when Integer object is used as a lock in synchronized block](https://gist.github.com/engineerscodes/312780a6c710a9d7ba0a87b074c2c9f0)
  2) [Primitive Wrapper Classes are Immutable in Java](https://www.geeksforgeeks.org/primitive-wrapper-classes-are-immutable-in-java/)
+ 3) [context switch in synchronized method and block](https://gist.github.com/engineerscodes/d6c06a86a84ee4c78db9f153ceb691af)