This page contains a set of basic exercises that you need to complete along with your beginning Java notes. Exercises are divided into modules similar to the modules for multiple choice questions. Practice these alongside reading notes and answering the multiple choice questions.
Write a HelloWorld program. Write a simple program with a main method that prints Hello World.
Write a program using packages. Create a class that is part of a package 'com.javajee.examples'. Compile and execute it.
DATA TYPES AND VARIABLES
Write a program with static, instance and local variables. Write a class that has 2 variables of type int: myStaticVar, myInstanceVar and myLocalVar as a static instance and local variable respectively. Assign values to static and instance variables through appropriate initialization blocks, and local variable within the method where it is defined. Print their values from main method in most appropriate way.
Write a program to demonstrate static import. Create class Abc in package com.javajee.examples.First with a static variable myStaticVar. Assign it a value of 10. Create another class Def in the package com.javajee.examples.second. Import myStaticVar of class Abc through static import and print its value from a main method.
METHODS AND CONSTRUCTORS
Create a Calculator class. Create a class Calculator with two static methods add and subtract, that accept two integers and does addition/subtraction and return an integer result. Pass values, get the result and print them all from main method.
OVERLOADING METHODS AND CONSTRUCTORS
Create a class with two overloaded constructors: one that accept an int and other that accept two int. Invoke the one that accept only one int from the main method for creating an object. This 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. 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.
OPERATORS AND SCOPES
Write a program with an instance variable and local variable with same name. Assign different values along with their declarations. Print both values from the method where the local variable is defined in the order: local variable, instance variable.
Create a program that demonstrates a switch statement with default case. Add appropriate break statements.
Create a program that demonstrates an if, else if and else.
Create a for loop, while loop and do-while loop that print from 1 to 10.
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.
Create an interface InterA with a single method. Create a class that implement that interface.
Create an Abstract class with one abstract and one concrete method. Create a concrete child class that extend the abstract class.
CASTING AND INSTANCEOF
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.
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.
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.
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.
Create a program to demonstrate the keywords throw, throws, try, catch and finally.
Create an interface InterA with a single method. Create an anonymous inner class that implement that interface and invoke that method.
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