This page contains a set of basic exercises that you need to complete along with your beginning Java notes. Exercises are divided into topics similar to the topics mentioned in the multiple choice questions. Practice these alongside reading notes and answering the multiple choice questions.

JPA 1 - Module 1: Java Essentials

Notes: https://javajee.com/book/java-101-getting-started-with-java

Topic 1: Java Basics

1. Write a HelloWorld program. Write a simple program with a main method that prints Hello World.

2. Use package and import statement.

   1. Create a class Hello1 that is part of a package com.javajee.package1.

      1. Add the standard main method that will be invoked by JVM.

      2. Add one more method main with same signature as the standard main class, but with no arguments.

      3. Compile and execute it.

   2. Create another class Hello2 that is part of another package com.javajee.package2.

      1. Import the class Hello1

      2. Add the standard main method that will be invoked by JVM.

      3. Invoke the main method of Hello1 that does not take any arguments from this main method as: Hello1.main();

      4. Remove the import statement and invoke the same method using the fully qualified name of the class.

Question sets:

With answers: set-1, set-3

Without answers: set-2

JPA 1 - Module 2: Java Core - Classes, Objects, Variables and Methods

Notes: https://javajee.com/book/java-core-classes-objects-variables-and-methods

Topic 1: Data Types and Variables

1. Write a program with static, instance and local variables.

   1. Write a class that has 2 variables of type int: myStaticVar, myInstanceVar and myLocalVar as a static instance and local variable respectively.

   2. Assign values to static and instance variables through appropriate initialization blocks, and local variable within the method where it is defined.

   3. Print their values from main method in most appropriate way.

2. Write a program to demonstrate static import.

   1. Create class Abc in package com.javajee.examples.First with a static variable myStaticVar.

   2. Assign it a value of 10. 

   3. Create another class Def in the package com.javajee.examples.second.

   4. Import myStaticVar of class Abc through static import and print its value from a main method.

Question sets:

With answers: set-4, set-6

Without answers: set-5

Topic 2: methods and constructors

1. Create a Calculator class.

   1. Create a class Calculator with two static methods add and subtract, that accept two integers and does addition/subtraction and return an integer result.  

   2. Pass values, get the result and print them all from main method.

Question sets:

With answers: set-7, set-9

Without answers: set-8

Topic 3: Overloading methods and constructors

1. Create a class with overloaded constructors.

   1. Create a class with two overloaded constructors: one that accept an int and other that accept two int.

   2. Invoke the one that accept only one int from the main method for creating an object.

   3. The constructor should then call the other constructor passing in the passed in argument as the first argument and some default value for the second argument.

   4. Constructor 1 should print "I am constructor that accept an int: value" where value is the value passed in and constructor 2 should print "I am a constructor that accept two int: value1, value2" where value1 and value2 are the values passed in as parameters.

Question sets:

With answers: set-10

Without answers: set-11

JPA 1 - Module 3: Operators, Decision and Looping Constructs

Notes: https://javajee.com/book/java-core-operators-decision-and-looping-constr...

Topic 1: Operators and scopes

1. Program with instance variable and local variable.

   1. Write a program with an instance variable and local variable with same name.

   2. Assign different values along with their declarations.

   3. Print both values from the method where the local variable is defined in the order: local variable, instance variable.

Question sets:

With answers: set-12

Without answers: set-13

Topic 2: Decision constructs

1. Create a program that demonstrates a switch statement with default case. Add appropriate break statements.

2. Create a program that demonstrates an if, else if and else.

Question sets:

With answers: set-14, set-16

Without answers: set-15

Topic 3: Looping constructs

1. Create a for loop, while loop and do-while loop that print from 1 to 10.

Question sets:

With answers: set-17, set-19

Without answers: set-18

JPA 1 - Module 4: Object Oriented Programming

Notes: https://javajee.com/book/java-core-object-oriented-programming

Topic 1: Inheritance

1. Create class Abc in a package with a protected variable. Create another class Def in another package extending the class Abc and print the value of inherited protected variable.

Question sets:

With answers: set-20, set-22

Without answers: set-21

Topic 2: Abstraction

1. Create an interface InterA with a single method. Create a class that implement that interface.

2. Create an Abstract class with one abstract and one concrete method. Create a concrete child class that extend the abstract class.

Question sets:

With answers: set-23, set-25

Without answers: set-24

Topic 3: Casting and instanceof

1. Write a program to demonstrate casting. Create class Abc. Create class Def that extend from Abc. Create a method m1() that print "I am m1 in Def" only in Def. Create an object of Def and assign it to a reference of Abc. Use casting to invoke the method m1() using the reference of type Abc using casting.

Question sets:

With answers: set-26

Without answers: set-27

JPA 1 - Module 5: Arrays and ArrayLists

Topic 1: Arrays

1. Write a method that accept two strings and check if two strings are anagrams (or permutations of each other). Example: "aaba" and "aaab" should return true. But "aaba" and "aabb" should return false. Test the method by passing positive and negative cases from the main method.

Question sets:

With answers: set-28, set-30

Without answers: set-29

Topic 2: ArrayList

1. Create an ArrayList object for holding String objects and an assign it to a List reference type. Add 5 string values to it. Print it using a for each loop.

2. Create an ArrayList object for holding String objects and an assign it to a List reference type. Add 5 string values to it. Print it using an Iterator without using the for each loop.

Question sets:

With answers: set-31

JPA 1 - Module 6: Exception Handling

Notes: https://javajee.com/book/java-core-exception-handling

Topic 1: Handling exceptions

1. Create a program to demonstrate the keywords throw, throws, try, catch and finally.

Question sets:

With answers: set-32, set-34

Without answers: set-33, set-35

JPA 1 - Module 7: Inner classes and more

Notes:

Inner class: https://javajee.com/book/java-core-classes-objects-variables-and-methods

Topic 1: Inner classes

1. Create an interface InterA with a single method. Create an anonymous inner class that implement that interface and invoke that method.