In String class equals() method is overridden for content comparison. Hence s1.equals(s2) returns true.

== operator is always meant for reference/address comparison.Hence s1==s2 returns false.

Whenever we are using System.exit(0) then JVM will be terminated. In this case finally block won't be executed.

To use == operator between object references, compulsory there should be some relation between argument types (either parent to child or child to parent or same type), otherwise we will get compile time error.

In the above example there is no relation between String and StringBuilder. Hence we will get compile time error saying: incomparable types: String and StringBuilder

Whenever we are using curly braces for lambda expressions body, then to return value we should use return keyword explicitly.

After applying all the operations, the content of StringBuilder is ava. Hence the output is: ava 3

If catch block and finally block throws exceptions, then only finally block thrown exception(most recently raised exception) will be displayed to the console. Hence NullPointerException in the above program.