Use case diagram, activity diagram, Collaboration diagram. 

Use case diagram :

It describes the business environment. Its primary goal is to show the series of events and actions within any given process that will be performed by an actor.  

Activity diagram:

The activity diagram is important because it gives an outline of the work flow within the business as well as the activities and action completed. 

For instance with a company, there is likely to be more than one department. In such a case each department, will have different access levels to the system. 

So if there’s a Medical, HR and Accounts team they will only have access to screens that relate to each. 

The activity diagram will highlight the differences within the departments which will be very helpful for developers when they are designing and coding. 

Collaboration diagram:

A collaboration diagram, also called a communication diagram or interaction diagram, is an illustration of the relationships and interactions among software objects in the Unified Modeling Language (UML). The concept is more than a decade old although it has been refined as modeling paradigms have evolved. 

long lastModified();

we can give this return value to a date object and we can get data to be displayed.

Outside the package if any other class other than JVM calls the finalize method our class then it is not allowed

use super keyword.

super keyword points immediate super class.

Class Sample {

int a =23;

 }

Class Sub extends Sample { 

 String a = "bablu";

 void show() {

 System.out.println(a); //bablu

 System. out. println(this.a); //bablu

 System. out.println(super.a); //23

}

}

Class Demo {

Public static void main(string[] args) {

sub s = new Sub();

s.show();

}

}

yes if the method is ovreriding method

no if the method is not overriding method

Path contains path of .exe files(commands).

Classpath contains path of packages. packages can be stored in folder or .jar files

String class objects are immutable objects and they represents strings( sequence of characters)

StringBuffer class objects are mutable objects representing strings and they are Thread safe

StringBuild class objects are also mutable objects representing strings and they are not Thread safe

Method contains name, parameters, return type and executable body. But block does not contains name, parameters, return type.It contains only executable body.

Methods are executed by method call statements. Blocks are executed automatically with class loading and with object creation.