The main method is the entry point to a desktop based core Java application.

Previously, we created our first Java program "Hello.java" as:

public class Hello {

  public static void main(String[] args)

  {

     System.out.println("Hello");

  }

}

We then compiled it using javac as:

javac Hello.java 

We then executed it as:

java Hello

And output was:

Hello

String interning is a method of storing only one copy of each distinct string value. Strings in Java are immutable and hence this sharing is perfectly safe and give you better performance. The distinct values are stored in a fixed-size hashtable usually referred to as string intern pool or string pool. The single copy of each string is called its 'intern'. You can read more about the basics of String interning with examples @ string-interning-in-java-with-examples.

Deadlock involves a mutual interdependence between two or more threads. 

This is a quick reference of constructors for various Stream classes.

You can quickly find out what all type of resources or streams a Stream class can be attached with. For instance, a BufferedReader do not have a constructor that can accept an InputStream, however an InputStreamReader has such a constructor that can accept an InputStream. So to use an InputStream such as System.in, we can attach it to an InputStreamReader and then attach the InputStreamReader to a BufferedReader as:

Let us do a simple hands on excercise followed by some questions to understand exceptions better. For theory and concetps of exceptions in Java. you can refer to the note introduction-to-exceptions-in-java. 

Exercise

Create a class MyClass and create three methods myMethod1(), Method2() and Method3().

Invoke Method2() from Method1() and Method3() from Method2().